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THE FORMATION OF VEGETABLE MOULD 
THROUGH THE ACTION OF WORMS 



i. r 



THE FpRMATION OF 
VEGETABLE MOULD 

THROUGH THE ACTION OF WORMS 
WITH OBSERVATIONS ON THEIR HABITS 

BY CHARLES DARWIN, LL.D., F.R.S. 

I 

THIRTEENTH THOUSAND 
WITH ILLUSTRATIONS 



i 



t. 



LONDON 

JOHN MURRAY, ALBEMARLE STREET 

S904 



y\ 



THE NEW YORK 
PUBLIC LIBRARY 

482099A 

A3T0R, LENOX AND 

TILDSN FOUNDATIONS 

a 1(^30 L 



I'llINTKD BV 

WILLIAM CLOWBS AND SONS, LIMITXI>) 

LONDON AND BBCCLXS. 



CONTENTS. 



Introduction Paget i-6 

CHAPTER I. 

HABITS OP WOKMS. 

Nature of the sites inhabited— Gun lire long under watei^— Noctunal 
—Wander about at night— Often lie doae to the months of their 
burrows, and are thus destroyed in laigp nnmbeis by birds— 
Structure— I>o not possess eyes, but can distinguish between 
lig^t and darhness— Retreat rapidly when brightly illuminated* 
not by a reflex action— Power of attention— Sensithre to heat 
and cold— Completely deaf— Sensitive to vibrations and to touch 
— Feeble power of smell— Taste — Mental qualities— Nature of 
food — Ommvorotts— Digestion— LeaTcs, before beii% swallowed, 
moistened with a fluid of the nature of the pancreatic secretion 
— Extra-stomachal digestion — Caldfeious glands^ structure of— 
Calcareous c o ncr eti ons formed in the anterior pair of glands — 
The^ calcareous matter primarily an excretion, but secondarily 
serves to neutralise the acids generated during the digestive 
process 7-Si 

CHAPTER II. 

HABITS OF WORMS— «M/irMWA/. 

Manner in which worms seise objects— Their power of suction— The 
instinct of plugging up the mouths of their burrows — Stones piled 
over the burrows— The advantages thus gained— Intelligence 



VI CONTENTS. 

shown by worms in their manner of plugging np their burrows 
—Various kinds of leaves and other objects thus used— Triangles 
of paper— Sommaiy of reasons for believii^ that worms exhibit 
some intelligence— Means by which they excavate their burrows, 
by pushing away the earth and swallowing it— Earth also swallowed 
for the nutritious matter whidi it contains— Depth to which worms 
burrow, and the construction of their burrows— Burrows Uned with 
castings, and in the upper part with leaves— The lowest part 
paved with little stones or seeds— Manner in which the castmgs 
are ejected— The collapse of old burrows— Distribution of worms 
— Toweflike castings in Bengal— Gigantic castings on the Nilgiri 
Mountains— Castings ejected in all countries . Pages 52-x^o 



CHAPTER III. 

THE AMOUNT OP FINE EARTH BROUGHT UP BY WORMS 
TO THE SURFACE. 

Rate at which various objects strewed on the sur&ce of grass-fields 
are covered up by the castings of worms — ^The bwial of a paved 
path— The slow subiidenoe of great stones left on the surface 
— ^The number of worms which live within a given space — 
The weight of earth ejected from a bunow, and from all the 
burrows within a given space— The thickness of the layer of 
mould which the castings on a given space would form within 
a given time if nnifovmly spread out— The slow rate at which 
mould can increase to a great thickness — Conclusion • 131*163 



CHAPTER IV. 

THE PART WHICH WORMS HAVE PLAYED IN TUB BURIAL 
OF ANCIENT BUILDINGS. 

The accnmulation of rubbish on the sites of great cities independent 
of the action of worms— The burial of a Roman villa at Abinger 
— ^The floors and walls penetrated by worms— Subsidence of a 
modem pavement — ^The buried pavement at Beaulieu Abbey — 
Roman villas at Chedworth and Brading— The remains of the 
Roman town at Silchestcr— The nature of the debris by which 
the remains are covered— The penetration of the tesselated 



CONTENTS. VII 

floon and walls by worms^-Sabodence of the floofs— TUdmeas 
of the moDld-- The old Roman dty of Wfoxeter— Thicknets 
of the mould— Depth of the ibimdatkms of tome of die btiildiBgi 
—Conclusion Pages i64r908 



CHAPTER V. 

THE ACTION OF WORMS IN THE DENUDATION OP THE LAND. 

Evidence of the amount of denudation which the land has vndexsone— 
Sub-aerial denudation— The deposition of dust — Vegetable mould, 
its dark colour and fine texture largely due to the action of worms 
— The disintegration of rocks by the humus-adds — Similar adds 
apparently generated within the bodies of worms— The action 
<d these acids Csdlitated by the continued movement of the 
partides of earth — A thick bed of mould chedu the disintegration 
of the underlying soil and, rocks — Partides of stone worn or 
triturated in die gissards of worms — Swallowed stones serve as 
millstones— The levigated state of the castings— Fragment of 
brick in the eastings over ancient buildings well roundedi The 
triturating power of worms not quite insignificant under a 
geological point of view 909-336 



CHAPTER VI. 

THE DENUDATION OF THE LAND— <VI»/SmMV^. 

Denudation aided by recently ejected castings flowing down inclined 
grass-covered sur&ces— The amount of earth which annually flows 
downwards— The effect of tropical rain on worm-castings— The 
finest partides of earth washed completely away from castings 
— ^The disintegration of dried castings into pellets, and thdr 
rolling down inclined surfaces— The formation of little ledges on 
bill-sides, in part due to the accumulation of disintegrated castings 
— Castings blown to leeward over level land — An attempt to 
estimate the amount thus blown— The degradation of andent 
encampments and tumuli — The preservation of the crowns and 
furrows on land andently ploughed — ^The formation and amount 
of mould over the Chalk formation . • . . 237-279 



VUl CONTENTS. 

CHAPTER VII. 

CONCLUSION. 

Sammary of the part which worms have played in the history of tl 
world — ^Tbeir aid in the disintegration of rocks— In the denacj 
tiOD of the land — ^In the preservation of ancient remains — In t 
prepaiation of the soil for the growth of plants— Mental pow< 
of worms-— Conclusion Pages 280-2 



INOXX 289-2 



THE FORMATION 



OP 



VEGETABLE MOULD, 

THROUGH THE ACTION OF WORMS, 
WITH OBSERVATIONS ON THEIR HABITS. 



INTRODUCTION. 

The share which worms have taken in the 
formation of the layer of vegetable mould, 
which covers the whole surface of the land in 
every moderately humid country, is the subject 
of the present volume. This mould is generally 
of a blackish colour and a few inches in thick- 
ness. In different districts it differs but little 
in appearance, although it may rest on various 
subsoils. The uniform fineness of the particles 
of which it is composed is one of its chief 
characteristic features ; and this may be well 
observed in any gravelly country, where a 
recently-ploughed field immediately adjoins 
one which has long remained imdisturbed for 
pasture, and where the v^etable mould is 



2 INTRODUCTION. 

exposed on the sides of a ditch or hole. Th< 
subject may appear an insignificant one» but wi 
shall see that it possesses some interest ; an( 
the maxim '' de minimis non curat lex/' doe 
not apply to science. Even £lie de Beaumont 
who generally undervalues small agencies anc 
their accumulated effects, remarks :* " La couchi 
'' tr^s-mince de la terre v^g6tale est un monu 
'' ment d'une haute antiquitd, et, par le fait d< 
''sa permanence, un objet digne d'occuper L 
^'g^ologue, et capable de lui foumir des re 
" marques int^ressantes/' Although the super 
ficial layer of vegetable mould as a whole m 
doubt is of the highest antiquity, yet in regan 
to its permanence, we shall hereafter see reasoi 
to believe that its component particles are i: 
most cases removed at not a very slow rate 
and are replaced by others due to the disinte 
gration of the underlying materials. 

As I was led to keep in my study durin 
many months worms in pots filled with earth, 
became interested in them, and wished to lear 
how far they acted consciously, and how muci 
mental power they displayed. I was the mor 
desirous to learn something on this head, a 
few observations of this kind have been made 

* ' Lemons de G^logie Pratique,* torn. i. 1845, p. 140. 



INTRODUCTION, 3 

as far as I know, on animals so low in the scale 
of organization and so poorly provided with 
sense-organs, as are earth-worms. 

In the year 1837, a short paper was read by 
me before the Geological Society of London,* 
'' On the Formation of Mould/' in which it was 
shown that small fragments of burnt marl, 
cinders, &c., which had been thickly strewed 
over the surface of several meadows, were found 
after a few years lying at the depth of some 
inches beneath the turf, but still forming a 
layer. This apparent sinking of superficial 
bodies is due, as was first suggested to me by 
Mr. Wedgwood of Maer Hall in Staffordshire, 
to the large quantity of fine earth continually 
brought up to the surface by worms in the form 
of castings. These castings are sooner or later 
spread out and cover up any object left on the 
surface. I was thus led to conclude that all 
the vegetable mould over the whole country 
has passed many times through, and will again 
pass many times through, the intestinal canals 
of worms. Hence the term '' animal mould " 
would be in some respects more appropriate 
than that commonly used of '' vegetable mould." 

* ' Transactions Geolog. Soc/ vol. v. p. 505. Read Novem- 
ber 1, 1837. 



4 INTRODUCTION. 

Ten years after the publication of m) 
paper, M. D'Archiac, evidently influenced b) 
the doctrines of Elie de Beaumont, wrote 
about my ''singuli^re th^orie," and objected 
that it could apply only to '' les prairies basses 
et humides;'* and that "les terres labourite 
les bois, les prairies ^ev6es, n'apportent aucune 
preuve k Tappui de cette maniere de voir."* 
But M. D'Archiac must have thus argued from 
inner consciousness and not from observation, 
for worms abound to an extraordinary degree 
in kitchen gardens where the soil is continually 
worked, though in such loose soil they generally 
deposit their castings in any open cavities ot 
within their old burrows instead of on the 
surface. Hensen estimates that there are 
about twice as many worms in gardens as 
in com-fields.t With respect to " prairies 
6lev6es/' I do not know how it may be in 
France, but nowhere in England have I seen 
the ground so thickly covered with castings 
as on commons, at a height of several hundre4 
feet above the sea. In woods again, if the 
loose leaves in autumn are removed, the whole 

* ' Histoire des progr^s de la Gdologie/ tom. i. 1847, p. 224. 
t ' Zdtschrift fiir wissenschaft. Zoologie,' B. xxviii. 1877, 
p. 361. 



INTRODUCTION. 5 

surface will be found strewed with castings. 
Dr. King, the superintendent of the Botanic 
Garden in Calcutta, to whose kindness I am 
indebted for many observations on earth- 
worms, informs me that he found, near Nancy 
in France, the bottom of the State forests 
covered over many acres with a spongy layer, 
composed of dead leaves and innumerable 
worm-castings. He there heard the Professor 
of "Am^nagement des For6ts" lecturing to 
his pupils, and pointing out this case as a 
''beautiful example of the natural cultivation 
" of the soil ; for year after year the thrown-up 
"castings cover the dead leaves; the result 
'* being a rich humus of great thickness.'' 

In the year 1869, Mr. Fish* rejected my 
conclusions with respect to the part which 
worms have played in the formation of vege- 
table mould, merely on account of their assumed 
incapacity to do so much work. He remarks 
that '' considering their weakness and their 
" size, the work they are represented to have 
*' accomplished is stupendous.'' Here we have 
an instance of that inability to sum up the 
effects of a continually recurrent cause, which 
has often retarded the progress of science, as 

* 'Gardeners' Chronicle,' April I7» 1869, p. 418. 



6 INTRODUCTION. 

formerly in the case of geology, and more 
recently in that of the principle of evolution. 

Although these several objections seemec 
to me to have no weight, yet I resolved tc 
make more observations of the same kind da 
those published, and to attack the problem or 
another side ; namely, to weigh all the cast 
ings thrown up within a given time in s 
measured space, instead of ascertaining th( 
rate at which objects left on the surface wen 
buried by worms. But some of my observa 
tions have been rendered almost superfluous 
by an admirable paper by Hensen, alread] 
alluded to, which appeared in 1877.* Befon 
entering on details with respect to the castings 
it will be advisable to give some account of th< 
habits of worms from my own observations anc 
from those of other naturalists. 

* Mr. Darwin's attention was called by Professor Hensen tc 
P. E. Miiller's work on Humus in * Tidsskrift for Skovbrug, 
Band iii. Heft i and 2, Copenhagen, 1878. He had, however 
no opportunity of consulting Miiller's work. Dr. Miiller pub 
lished a second paper in 1884 in the same periodical— a Danisl 
journal of forestry. His results have also been published ii 
German, in a volume entitled ' Studien iiber die natiirlichei 
Humusfbrmen, unter deren Einwirkung auf Vegetation unc 
Boden,' 8vo., Berlin, 1887. 

[First Edition, 
OcMfT lothy 1881.] 



CHx\P. I. { 7 ) 



CHAPTER I. 

HABITS OF WORMS. 

Nature of the sites inhabited — Can live long under water— 
Nocturnal— Wander about at night— Often lie close to the 
mouths of their burrows, and are thus destroyed in large 
numbers by birds— Structure — Do not possess eyes, but 
can distinguish between light and darkness — Retreat 
rapidly when brightly iUuminated, not by a reflex action— 
Power of attention— Sensitive to heat and cold — Com- 
pletely deaf— Sensitive to vibrations and to touch— Feeble 
power of smell— Taste — Mental qualities— Nature of food 
— Omnivorous — Digestion — Leaves before being swallowed, 
moistened with a fluid of the nature of the pancreatic 
secretion — Extra-stomachal digestion — Calciferous glands, 
structure of—- Calcareous concretions formed in the anterior 
pair of glands— The calcareous matter prinuurily an excre- 
tion, but secondarily serves to neutralise the acids generated 
during the digestive process. 

Earth-worms are distributed throughout the 
world under the form of a few genera, which 
externally are closely similar to one another. 
The British species of Lumbricus have never 
been carefully monographed; but we may 
judge of their probable number from those 
inhabiting neighbouring countries. In Scan- 
dinavia there are eight species, according to 



8 HABITS OF WORMS. CHAP. I. 

Eisen ; * but two of these rarely burrow in the 
groundi and one inhabits very wet places or 
even lives under the water. We are here con- 
cerned only with the kinds which bring up 
earth to the surface in the form of castings. 
Hoffmeister sajrs that the species in Germany 
are not well known, but gives the same number 
as Eisen, together with some strongly marked 

varieties.t 

Earth-worms abound in England in many 
different stations. Their castings may be seen 
in extraordinary numbers on commons and 
chalk-downs, so as almost to cover the whole 
surface, where the soil b poor and the grass 
short and thin. But they are almost or quite 
as numerous in some of the London parks, 
where the grass grows well and the soil appears 
rich. Even on the same field worms are much 
more frequent in some places than in others, 
without any visible difference in the nature of 
the soil They abound in paved court-yards 
dose to houses ; and an instance will be given 
in which they had burrowed through the floor 
of a very damp cellar. I have seen worms in 

* ^ Bidrag till Skandinaviens Oligochaetfaunay' 1871. 
t * Die bis jetzt bekannten Arten aus der Familie der 
Regenwiinner/ 1845. 



CHAP. I. SITES INHABITED. 9 

black peat in a boggy field ; but they are ex- 
tremely rare, or quite absent in the drier, 
brown, fibrous peat, which is so much valued 
by gardeners. On dry, sandy or gravelly 
tracks, where heath with some gorse, ferns, 
coarse grass, moss and lichens alone grow, 
hardly any worms can be found. But in many 
parts of England, wherever a path crosses a 
heath, its surface becomes covered with a fine 
short sward. Whether this change of vegeta- 
tion is due to the taller plants being killed by 
the occasional trampling of man and animals, 
or to the soil being occasionally manured by 
the droppings from animals, I do not know.* 
On such grassy paths worm-castings may often 
be seen. On a heath in Surrey, which was 
carefully examined, there were only a few 
castings on these paths, where they were much 
inclined ; but on the more level parts, where a 
bed of fine earth had been washed down from 
the steeper parts and had accumulated to a 

* There is even some reason to believe that pressure is 
actually favourable to the growth of grasses, for Professor 
Buckman, who made many observations on their growth in the 
experimental gardens of the Royal Agricultural College, re- 
marks ('Gardeners* Chronicle,' 1854, p. 619): ** Another 
circumstance in the cultivation of grasses in the separate form 
or small patches, is the impossibility of rolling or treading 
them firmly, without which no pasture can continue good." 



lO HABITS OF WORMS. CHAP. I* 

thickness of a few inches, worm-castings 
abounded These spots seemed to be over- 
stocked with worms, so that they had been 
compelled to spread to a distance of a few feet 
from the grassy paths, and here their castings 
had been thrown up among the heath; but 
beyond this limit, not a single casting could be 
found. A layer, though a thin one, of fine 
earth, which probably long retains some 
moisture, is in all cases, as I believe, necessary 
for their existence ; and the mere compression 
of the soil appears to be in some degree 
favourable to them, for they often abound in 
old gravel walks, and in foot-paths across 
fields. 

Beneath large trees few castings can be 
found during certain seasons of the year, and 
this is apparently due to the moisture having 
been sucked out of the ground by the innu- 
merable roots of the trees ; for such places 
may be seen covered with castings after the 
heavy autumnal rains. Although most cop- 
pices and woods support many worms, yet in a 
forest of tall and ancient beech-trees in Knole 
Park, where the ground beneath was bare of 
all v^etation, not a single casting could be 
found over wide spaces, even during the 



CHAP. I. WORMS TERRESTRIAL ANIMALS. II 

autumn. Nevertheless^ castings were abun- 
dant on some grass-covered glades and in- 
dentations which penetrated this forest On 
the mountains of North Wales and on the 
Alps, worms, as I have been informed^ are in 
most places rare ; and this may perhaps be 
due to the close proximity of the subjacent 
rocks, into which worms cannot burrow during 
the winter so as to escape being frozen. Dr. 
Mcintosh, however, found worm-castings at a 
height of 1500 feet on Schiehallion in Scotland. 
They are numerous on some hills near Turin 
at from 2000 to 3000 feet above the sea, and 
at a great altitude on the Nilgiri Mountains in 
South India and on the Himalaya. 

Earth-worms must be considered as terres- 
trial animals, though they are still in one sense 
semi-aquatic, like the other members of the 
great class of annelids to which they belong. 
M. Perrier found that their exposure to the 
dry air of a room for only a single night was 
fatal to them. On the other hand he kept 
several large worms alive for nearly four 
months, completely submerged in water.* 

* I shall have occasion often to refer to M. Terrier's admirable 
memoir, * Organisation des Lombriciens terrestres ' in * Archives 
de Zoolog. exp^r.' torn. iii. 1874, P- 372- ^« P* Morren (* De 
Lombrici terrestris Hist. Nat.' 1829, P* ^4) found that worms 



12 HABITS OF WORMS. CHAP. I. 

During the summer when the ground is dry, 
they penetrate to a considerable depth and 
cease to work, as they do during the winter 
when the ground is frozen. Worms are 
nocturnal in their habits, and at night may be 
seen crawling about in large numbers, but 
usually with their tails still inserted in their 
burrows. By the expansion of this part of their 
bodies, and with the help of the short, slightly 
reflexed bristles, with which their bodies are 
armed, they hold so fast that they can seldom 
be dragged out of the ground without being 
torn into pieces.* During the day they remain 
in their burrows, except at the pairing season, 
when those which inhabit adjoining burrows 
expose the greater part of their bodies for an 
hour or two in the early morning. Sick 
individuals, which are generally affected by 
the parasitic larvae of a fly, must also be ex- | 
cepted, as they wander about during the day , 
and die on the surface. After heavy rain i 
succeeding dry weather, an astonishing number / 
of dead worms may sometimes be seen lying ' 
on the ground. Mr. Galton informs me that ( 

endured immersion for fifteen to twenty days in summer, but 
that in winter they died when thus treated. 

* Morren, *De Lumbrici terrestris Hist. Nat.' &c., 1829, 
p. 67. 



CHAP. I. NOCTURNAL. 1 3 

on one such occasion (March, 1881), the dead 
worms averaged one for every two and a half 
paces in length on a walk in Hyde Park, four 
paces in width. He counted no less than 45 
dead worms in one place in a length of sixteen 
paces. From, the facts above given, it is not 
probable that these worms could have been 
drowned, and if they had been drowned they 
would have perished in their burrows. I 
believe that they were already sick, and that 
their deaths were merely hastened by the 
ground being flooded 

It has often been said that under ordinary 
circumstances healthy worms never, or very 
rarely, completely leave their burrows at night ; 
but this is an error, as White of Selbome long 
ago knew. In the morning, after there has 
been heavy rain, the film of mud or of very 
fine sand over gravel-walks is often plainly 
marked with their tracks. I have noticed this 
from August to May, both months included, 
and it probably occiu^ during the two remaining 
months of the year when they are wet. On 
these occasions, very few dead worms could 
anywhere be seen. On January 31, 1881, after 
a long-continued and unusually severe frost 
with much snow, as soon as a thaw set in, the 



14 HABITS OF WORMS. CHAP. I. 

walks were marked with innumerable tracks. 
On one occasion, five tracks were counted 
crossing a space of only an inch square. They 
could sometimes be traced either to or from the 
mouths of the burrows in the gravel-walks, for 
distances between 2 or 3 up to 15 yards. I 
have never seen two tracks leading to the same 
burrow; nor is it likely, from what we shall 
presently see of their sense-organs, that a worm 
could find its way back to its burrow after 
having once left it. They apparently leave 
their burrows on a voyage of discovery, and 
thus they find new sites to inhabit. 

Morren states* that worms often lie for 
hours almost motionless dose beneath the 
mouths of their burrows. I have occasionally 
noticed the same fact with worms kept in pots 
in the house; so that by looking down into 
their burrows, their heads could just be seen. 
If the ejected earth or rubbish over the burrows 
be suddenly removed, the end of the worm's 
body may very often be seen rapidly retreating. 
This habit of lying near the surface leads to 
their destruction to an immense extent. Every 
morning during certain seasons of the year, 
the thrushes and blackbirds on all the lawns 
* * De Lumbrici terrestris Hist. Nat.* &c., p. 14. 



CHAP. I. THEIR STRUCTURE. 1 5 

throughout the country draw out of their holes 
an astonishing number of worms ; and this they 
could not do» unless they lay dose to the sur- 
face. It is not probable that worms behave in 
this manner for the sake of breathing fresh air, 
for we have seen that they can live for a long 
time under water. I believe that they lie near 
the surface for the sake of warmth, especially 
in the morning; and we shall hereafter find 
that they often coat the mouths of their burrows 
with leaves, apparently to prevent their bodies 
from coming into close contact with the cold 
damp earth. It is said that they completely 
dose their burrows during the winter. 

Structure. — A few remarks must be made 
on this subject. The body of a large worm 
consists of from loo to 200 almost cylindrical 
rings or segments, each furnished with minute 
bristles. . The muscular system is well 
developed. Worms can crawl backwards as 
wdl as forwards, and by the aid of their 
affixed tails can retreat with extraordinary 
rapidity into their burrows. The mouth is 
situated at the anterior end of the body, and 
is provided with a little projection (lobe or lip, 
as it has been variously called) which is used 
for prehension. Internally, behind the mouth, 



1 6 HABITS OF WORMS. CHAP. I. 

there is a strong pharynx, shown in the ac- 
companying diagram (Fig. i) which is pushed 
forwards when the animal eats» and this part 
corresponds, according to Perrier, with the pro- 
trudable trunk or proboscis of other annelids. 
The pharynx leads into the oesophagus, on 
each side of which in the lower part there are 
three pairs of large glands, which secrete a 
surprising amount of carbonate of lime* These 
calciferous glands are highly remarkable, for 
nothing like them is known in any other 
animal. Their use will be discussed when we 
treat of the digestive process. In most of the 
species, the oesophagus is enlaiged into a crop 
in front of the gizzard. This latter organ is 
lined with a smooth thick chitinous membrane, 
and is surrounded by weak longitudinal, but 
powerful transverse muscles. Perrier saw 
these muscles in energetic action ; and, as he 
remarks, the trituration of the food must be 
chiefly effected by this organ, for worms possess 
no jaws or teeth of any kind. Grains of sand 
and small stones, from the i^ to a little more 
than the iV inch in diameter, may generally 
be found in their gizzards and intestines. As 
it is certain that worms swallow many little 
stones, independently of those swallowed while 



Mooth. 



Pharynx. 



CEsophagUii. 

^^ CaJciferous glaiids. 
CEsophagus. 



i/r 1 Crop. 



Gizzard. 



IJ^jf Upper part of in- 
testine. 



Fig. I. — Diagram of the 
alimentary canal of an 
earth-worm (Lumbri- 
cus), copied from Ray 
Lankester in ' Quart. 
Joum. of Microscop. 
Soc.' vol. XV. N.S. 
pi. vii. 




\-^^ 



Fig. 2.— -Tower-like casting from near Nice, con- 
structed of earth, voided probably by a species 
of Perichseta : of natural size, copied from a 
photograph. 

VTo/acep. i6. 



CHAP. I. THEIR SENSES. 1 7 

excavating their burrows, it is probable that they 
serve, like mill-stones, to triturate their food. 
The gizzard opens into the intestine, which runs 
in a straight course to the vent at the posterior 
end of the body. The intestine presents a 
remaricable structiu^ the typhlosolis, or, as the 
old anatomists called it, an intestine within an 
intestine ; and ClaparMe* has shown that this 
consists of a deep longitudinal involution of the 
walls of the intestine, by which means an 
extensive absorbent surface is gained. 

The circulatory system is well developed. 
Worms breathe by their skin, as they do not 
possess any special respiratory organs. The 
two sexes are united in the same individual, but 
two individuals pair together. The nervous 
system is fairly well developed ; and the two 
plmost confluent cerebral ganglia are situated 
very near to the anterior end of the body. 

Senses. — ^Worms are destitute of eyes, and 
at first I thought that they were quite in- 
sensible to light ; for those kept in confinement 
were repeatedly observed by the aid of a 
candle, and others out of doors by the aid of 
a lantern, yet they were rarely alarmed, 

* Histolog. Untersuchungen uber die Regenwiirmer. ' Zeit- 
schrift ftir wissenschaft. Zoologie,' B. xix., 1869, P* 61 1. 



1 8 HABITS OF WORMS. CHAP. I. 

although extremely timid animals. Other 
persons have found no difficulty in observing 
worms at night by the same means.* 

Hoffmeister, however, states f that worms, 
with the exception of a few individuals, are 
extremely sensitive to light; but he admits 
that in most cases a certain time is requisite 
for its action. These statements led me to 
watch on many successive nights worms kept 
in pots, which were protected from currents 
of air by means of glass plates* The pots 
were approached very gently, in order that 
no vibration of the floor should be caused. 
When under these circumstances worms were 
illuminated by a bulVs-eye lantern having 
slides of dark red and blue glass, which in- 
tercepted so much light that they could be seen 
only with some difficulty, they were not at all 
affected by this amount of light, however long 
they were exposed to it The light, as far as 
I could judge, was brighter than that from 
the full moon. Its colour apparently made 
no difference in the result. When they were 
illuminated by a candle, or even by a bright 

* For instance, Mr. Bridgpoian and Mr. Newman ('The 
Zoologist/ vol. viL 1849, p. 2576), and some friends who obsenred 
worms for me. 

t ' Familie der Regenwiirmer,' 1845, P- 'S* 



CHAP. I. THBIR SENSES. 19 

paraffin lamp, they were not usually aflfected 
at first. Nor were they when the light was 
alternately admitted and shut off. Some- 
times, however, they behaved very differ- 
ently, for as soon as the light fell on them, 
they withdrew into their burrows with almost 
instantaneous rapidity. This occurred per- 
haps once out of a dozen times. When they 
did not withdraw instantly, they often raised 
the anterior tapering ends of their bodies 
from the ground, as if their attention was 
aroused or as if surprise was felt; or they 
moved their bodies from side to side as if 
feeling for some object. They appeared dis- 
tressed by the light ; but I doubt whether this 
was really the case, for on two occasions after 
withdrawing slowly, they remained for a long 
time with their anterior extremities protruding 
a little from the mouths of their burrows, in 
which position they were ready for instant and 
complete withdrawal 

When the light from a candle was concen- 
trated by means of a large lens on the anterior 
extremity, they generally withdrew instantly; 
but this concentrated light failed to act perhaps 
once out of half a dozen trials. The light was 
on one occasion concentrated on a worm lying 



20 HABITS OF WORMS. CHAP. I. 

beneath water in a saucer, and it instantly 
withdrew into its burrow. In all cases the 
duration of the light, unless extremely feeble, 
made a great difference in the result; for 
worms left exposed before a paraffin lamp or 
a candle invariably retreated into their burrows 
within from five to fifteen minutes ; and if in 
the evening the pots were illuminated before 
the worms had come out of their burrows, 
they failed to appear. 

From the foregoing facts it is evident that 
light affects worms by its intensity and by its 
duration. It is only the anterior extremity of 
the body, where the cerebral ganglia lie, which 
is affected by light, as Hoffmeister asserts, and 
as I observed on many occasions. If this part 
is shaded, other parts of the body may be fully 
illuminated, and no effect will be produced As 
these animals have no eyes, we must suppose 
that the light passes through their skins, and 
in some manner excites their cerebral ganglia. 
It appeared at first probable that the different 
manner in which they were affected on different 
occasions might be explained, either by the 
degree of extension of their skin and its con- 
sequent transparency, or by some particular 
incident of the light ; but I could discover no 



CHAP. 1. THEIR SENSES. 21 

such relation. One thing was manifest, namely, 
that when worms were employed in dragging 
leaves into their burrows or in eating them, and 
even during the short intervals whilst they 
rested from their work, they either did not 
perceive the light or were regardless of it ; and 
this occurred even when the light was con- 
centrated on them through a large lens. So, 
again, whilst they are paired, they will remain 
for an hour or two out of their burrows, fully 
exposed to the morning light ; but it appears 
from what Hoflfmeister says that a light will 
occasionally cause paired individuals to separate. 
When a worm is suddenly illuminated and 
dashes like a rabbit into its burrow — ^to use 
die expression em^oyed by a friend — ^we are 
at first led to look at the action as a reflex one. 
The irritation of the cerebral ganglia appears 
to cause certain muscles to contract in an 
inevitable manner, independently of the will 
or consciousness of the animal, as if it were 
an automaton. But the different effect which 
a light produced on different occasions, and 
especially the fact that a worm when in any 
way employed and in the intervals of such 
employment, whatever set of muscles and 
ganglia may then have been brought into 



22 HABITS OF WORMS. CHAP. I. 

play, is often regardless of light, are opposed 
to the view of the sudden withdrawal being a 
simple reflex action. With the higher animals, 
when close attention to some object leads to 
the disregard of the impressions which other 
objects must be producing on them, we at- 
tribute this to their attention being then 
absorbed; and attention implies the presence 
of a mind. Every sportsman knows that he 
can approach animals whilst they are grazing, 
fighting or courting, much more easily than at 
other times. The state, also, of the nervous 
system of the higher animals differs much at 
different times, for instance, a horse is much 
more readily startled at one time than at an- 
other. The comparison here implied between 
the actions of one of the higher animals and 
of one so low in the scale as an earth-worm, 
may appear far-fetched ; for we thus attribute 
to the worm attention and some mental power, 
nevertheless I can see no reason to doubt the 
justice of the comparison. 

Although worms cannot be said to possess 
the power of vision, their sensitiveness to light 
enables them to distinguish between day and 
night; and they thus escape extreme danger 
from the many diurnal animals which prey on 



chap: I. THEIR SENSES. 23 

them. Their withdrawal into their burrows 
during the day appears, however, to have 
become an habitual action; for worms kept 
in pots covered by glass plates, over which 
sheets of black paper were spread, and placed 
before a north-east window, remained during 
the day-time in their burrows and came out 
every night; and they continued thus to act 
for a week. No doubt a little light may have 
entered between the sheets of glass and the 
blackened paper ; but we know from the trials 
with coloured glass, that worms are indifferent 
to a small amount of light. 

Worms appear to be less sensitive to 
moderate radiant heat than to a bright light 
I judge of this from having held at different 
times a poker heated to dull redness near 
some worms, at a distance which caused a 
very sensible degree of warmth in my hand. 
One of them took no notice ; a second with- 
drew into its burrow, but not quickly; the 
third and fourth much more quickly, and the 
fifth as quickly as possible. The light from 
a candle, concentrated by a lens and passing 
through a sheet of glass which would intercept 
most of the heat-rays, generally caused a much 
more rapid retreat than did the heated poker. 



24 HABITS OF WORMS. CHAP. I. 

Worms are sensitive to a low temperature, as 
may be inferred from their not coming out of 
their burrows during a frost. 

Worms do not possess any sense of hearing. 
They took not the least notice of the shrill 
notes from a metal whistle, which was re- 
peatedly sounded near them ; nor did they 
of the deepest and loudest tones of a bassoon. 
They were indifferent to shouts, if care was 
taken that the breath did not strike them. 
When placed on a table close to the keys 
of a piano, which was played as loudly as 
possible, they remained perfectly quiet 

Although they are indifferent to undula- 
tions in the air audible by us, they are ex- 
tremely sensitive to vibrations in any solid 
object When the pots containing two worms 
which had remained quite indifferent to the 
sound of the piano, were placed on this instru- 
ment, and the note C in the bass clef was 
struck, both instantly retreated into their bur- 
rows. After a time they emerged, and when 
G above the line in the treble clef was 
struck they again retreated. Under similar 
circumstances on another night one worm 
dashed into its burrow on a very high note 
being struck only once, and the other worm 



CHAP. I. THEIR SENSES. 2$ 

when C in the treble clef was struck. On 
these occasions the worms were not touching 
the sides of the pots, which stood in saucers ; 
so that the vibrations, before reaching their 
bodies, had to pass from the sounding board 
of the piano, through the saucer, the bottom 
of the pot and the damp, not very compact 
earth on which they lay with their tails in 
their burrows. They often showed their sensi- 
tiveness when the pot in which they lived, 
or the table on which the pot stood, was 
accidentally and lightly struck; but they ap- 
peared less sensitive to such jars than to the 
vibrations of the piano ; and their sensitiveness 
to jars varied much at different times. 

It has often been said that if the ground is 
beaten or otherwise made to tremble, worms 
believe that they are pursued by a mole and 
leave their burrows. * From one account that 
I have received, I have no doubt that this is 
often the case; but a gentleman informs me 
that he lately saw eight or ten worms leave 
their burrows and crawl about the grass on 
some boggy land on which two men had just 
trampled while setting a trap ; and this occurred 
in a part of Ireland where there were no moles. 
I have been assured by a Volunteer that he 



26 HABITS OF WORMS. CHAP. I. 

has often seen many large earth-worms crawl* 
ing quickly about the grass, a few minutes 
after his company had fired a volley with blank 
cartridges. The Peewit {Trtnga vaneUus^ 
Linn.) seems to know instinctively that worms 
will emerge if the ground is made to tremble ; 
for Bishop Stanley states (as I hear from Mr. 
Moorhouse) that a young peewit kept in con- 
finement used to stand on one leg and beat 
the turf with the other leg until the worms 
crawled out of their burrows, when they were 
instantly devoured. Nevertheless, worms do 
not invariably leave their burrows when the 
ground is made to tremble, as I know by 
having beaten it with a spade, but perhaps it 
was beaten too violently. 

The whole body of a worm is sensitive to 
contact A slight puff of air from the mouth 
causes an instant retreat The glass plates 
placed over the pots did not fit closely, and 
blowing through the very narrow chinks thus 
left, often sufficed to cause a rapid retreat 
They sometimes perceived the eddies in the 
air caused by qiiickly removing the glass 
plates. When a worm first comes out of its 
burrow, it generally moves the much extended 
anterior extremity of its body from side to 



CHAP. I. THEIR SENSES. ^^ 

side in all directions, apparently as an organ 
of touch ; and there is some reason to believe, 
as we shall see in the next chapter, that they 
are thus enabled to gain a general notion of 
the form of an object. Of all their senses 
that of touch, including in this term the per- 
ception of a vibration, seems much the most 
highly developed. 

In worms the sense of smell apparently is 
confined to the perception of certain odours, 
and is feeble. They were quite indifferent to 
my breath, as long as I breathed on them very 
gently. This was tried, because it appeared 
possible that they might thus be warned of 
the approach of an enemy. They exhibited 
the same indifference to my breath whilst I 
chewed some tobacco, and while a pellet of 
cotton-wool with a few drops of millefleurs 
perfume or of acetic acid was kept in my 
mouth. Pellets of cotton-wool soaked in 
tobacco juice, in millefleurs perfume, and in 
paraffin, were held with pincers and were 
waved about within two or three inches of 
several worms, but they took no notice. On 
one or two occasions, however, when acetic 
acid had been placed on the pellets, the worms 
appeared a little uneasy, and this was probably 



28 HABITS OF WORMS. CHAP. I. 

due to the irritation of their skins. The per- 
ception of such unnatural odours would be 
of no service to worms; and as such timid 
creatures would almost certainly exhibit some 
signs of any new impression, we may conclude 
that they did not perceive these odours. 

The result was different when cabbage- 
leaves and pieces of onion were employed, 
both of which are devoured with much relish 
by worms. Small square pieces of fresh and 
half-decayed cabbage-leaves and of onion bulbs 
were on nine occasions buried in my pots, 
beneath about I of an inch of common garden 
soil ; and they were always discovered by the 
worms. One bit of cabbage was discovered 
and removed in the course of two hours ; three 
were removed by the next morning, that is, 
after a single night; two others after two 
nights ; and the seventh bit after three nights. 
Two pieces of onion were discovered and 
removed after three nights. Bits of fresh raw 
meat, of which worms are very fond, were 
buried, and were not discovered within forty- 
eight hours, during which time they had not 
become putrid. The earth above the various 
buried objects was generally pressed down 
only slightly, so as not to prevent the emission 



CHAP. I. THEIR SENSES. 29 

of any odour. On two occasions^ however, 
the surface was well watered, and was thus 
rendered somewhat compact After the bits 
of cabbage and onion had been removed, 
I looked beneath them to see whether the 
worms had accidentally come up from below, 
but there was no sign of a burrow ; and twice 
the buried objects were laid on pieces of tin- 
foil which were not in the least displaced. It 
is of course possible that the worms whilst 
moving about on the surface of the ground, 
with their tails affixed within their burrows, 
may have poked their heads into the places 
where the above objects were buried; but I 
have never seen worms acting in this manner. 
Some pieces of cabbage-leaf and of onion were 
twice buried beneath very fine ferruginous 
sand, which was slightly pressed down and 
well watered, so as to be rendered very com- 
pact, and these pieces were never discovered. 
On a third occasion the same kind of sand was 
neither pressed down nor watered, and the 
pieces of cabbage were discovered and re- 
moved after the second night These several 
facts indicate that worms possess some power 
of smell ; and that they discover by this means 
odoriferous and much-coveted kinds of food. 



30 HABITS OF WORMS. CHAP. I. 

It may be presumed that all animals which 
feed on various substances possess the sense 
of taste, and this is certainly the case with 
worms. Cabbage-leaves are much liked by 
worms; and it appears that they can dis- 
tinguish between different varieties; but this 
may perhaps be owing to differences in their 
texture. On eleven occasions pieces of the 
fresh leaves of a conunon green variety and 
of the red variety used for pickling were 
given them, and they preferred the green, 
the red being either wholly neglected or much 
less gnawed. On two other occasions, how- 
ever, they seemed to prefer the red. Half- 
decayed leaves of the red variety and fresh 
leaves of the green were attacked about 
equally. When leaves of the cabbage, horse- 
radish (a favourite food) and of the onion were 
given together, the latter were always and 
manifestly preferred. Leaves of the cabbage, 
lime-tree, Ampelopsis, parsnip (Pastinaca), and 
celery (Apium) were likewise given together; 
and those of the celery were first eaten. But 
when leaves of cabbage, turnip, beet, celery, 
wild cherry and carrots were given together, 
the two latter kinds, especially those of the 
carrot, were preferred to all the others, 



CHAP. I. MENTAL QUALITIES. 3 1 

including those of celery. It was also manifest 
after many trials that wild cherry leaves were 
greatly preferred to those of the lime-tree and 
hazel (Corylus). According to Mr. Bridgman 
the half-decayed leaves of Phhx vema are 
particularly liked by worms.* 

Pieces of the leaves of cabbage, turnip, 
horse-radish and onion were left on the pots 
during 22 days, and were all attacked and had 
to be renewed ; but during the whole of this 
time leaves of an Artemisia and of the culinary 
sage, thyme and mint, mingled with the above 
leaves, were quite neglected excepting those 
of the mint, which were occasionally and very 
slightly nibbled. These latter four kinds of 
leaves do not differ in texture in a manner which 
could make them disagreeable to worms; they all 
have a strong taste, but so have the four first 
mentioned kinds of leaves ; and the wide differ- 
ence in the result must be attributed to a prefer- 
ence by the worms for one taste over another. 

Mental Qualities. — There is little to be 
said on this head. We have seen that worms 
are timid. It may be doubted whether they 
suffer as much pain when injured, as they 
seem to express by their contortions. Judging 

♦ * The Zoologist,' vol. vii. 1849, P- 2576. 



32 HABITS OF WORMS. CHAP. I. 

by their eagerness for certain kinds of food, 
they must enjoy the pleasure of eating. Their 
sexual passion is strong enough to overcome 
for a time their dread of light They perhaps 
have a trace of social feeling, for they are not 
disturbed by crawling over each other^s bodies, 
and they sometimes lie in contact According 
to HofTmeister they pass the winter either 
singly or rolled up with others into a ball at 
the bottom of their burrows.* Although 
worms are so remarkably deficient in the 
several sense-organs, this does not necessarily 
preclude intelligence, as we know from such 
cases as those of Laura Bridgman; and we 
have seen that when their attention is ei^raged, 
they neglect impressions to which they would 
otherwise have attended; and attention in- 
dicates the presence of a mind of some kind* 
They are also much more easily excited at 
certain times than at others. They perform 
a few actions instinctively, that is, all the 
individuals, including the young, perform such 
actions in nearly the same iashion. This is 

* < Familie der Regenwurmer,' p. 13. Dr. Sturtevant states 
in the * New York Weekly TritMine* (May 19, 1880) that he 
kept three worms in a pot, which was allowed to become 
extremely dry; and these worms were found "all entwined 
together, forming a round mass and in good condition." 



CHAP. I. FOOD AND DIGESTION. 33 

shown by the manner in which the species of 
Perichaeta eject their castings, so as to con- 
struct towers; also by the manner in which 
the burrows of the common earth-worm are 
smoothly lined with fine earth and often with 
little stones, and the mouths of their burrows 
with leaves. One of their strongest instincts 
is the plugging up the mouths of their burrows 
with various objects; and very young worms 
act in this manner. But some degree of in- 
telligence appears, as we shall see in the next 
chapter, to be exhibited in this work, — a result 
which has surprised me more than anything 
else in regard to worms. 

Food and Digestion. — Worms are omnivo- 
rous. They swallow an enormous quantity of 
earth, out of which they extract any digestible 
matter which it may contain ; but to this 
subject I must recur. They also consume a 
large number of half-decayed leaves of all 
kinds, excepting a few which have an un- 
pleasant taste or are too tough for them ; like- 
wise petioles, peduncles, and decayed flowers. 
But they will also consume fresh leaves, as 
I have found by repeated trials. According 
to Morren* they will eat particles of sugar 

♦ * De Lumbrici terrestris Hist. Nat.' p. 19. 

D 



34 HABITS OF WORMS. CHAP. I. 

and liquorice; and the worms which I kept 
drew many bits of dry starch into their burrows, 
and a large bit had its angles well rounded by 
the fluid poured out of their mouths. But as 
they often drag particles of soft stone, such 
as of chalk, into their burrows, I feel some 
doubt whether the starch was used as food. 
Pieces of raw and roasted meat were fixed 
several times by long pins to the surface of the 
soil in my pots, and night after night the 
worms could be seen tugging at them, with 
the edges of the pieces engulfed in their 
mouths, so that much was consumed. Raw 
fat seems to be preferred even to raw meat or 
to any other substance which was given them, 
and much was consumed. They are cannibals, 
for the two halves of a dead worm placed in 
two of the pots were dragged into the burrows 
and gnawed ; but as far as I could judge, they 
prefer fresh to putrid meat, and in so far I 
differ from HofTmeister. 

Lton Fredericq states * that the digestive 



* 'Archives de Zoologie exp^rimentale,' torn. viL 1878, p. 
394* When I wrote the above passage, I was not aware that 
Krukenberg Untersuchungen a. d. pbysioL Inst. d. Univ. 
Heidelberg,' Bd. ii. p. 37, 1877) had previously investigated the 
digestive juice of Lumbricus. He states that it contains a 
peptic, and diastatic, as well as a ttyptic ferment 



CHAP. I. FOOD AND DIGESTION. 35 

fluid of worms is of the same nature as the 
pancreatic secretion of the higher animals ; and 
this conclusion agrees perfectly with the kinds 
of food which worms consume. Pancreatic 
juice emulsifies fat, and we have just seen how 
greedily worms devour fat ; it dissolves fibrin, 
and worms eat raw meat; it converts starch 
into grape-sugar with wonderful rapidity, and 
we shall presently show that the digestive fluid 
of worms acts on starch.* But they live chiefly 
on half-decayed leaves; and these would be 
useless to them unless they could digest the 
cellulose forming the cell-walls; for it is well 
known that all other nutritious substances 
are almost completely withdrawn from leaves, 
shortly before they fall off* It has, however, 
now been ascertained that some forms of 
cellulose, though very little or not at all 
attacked by the gastric secretion of the 
higher animals, are acted on by that from the 
pancreas.t 

The half-decayed or fresh leaves which 
worms intend to devour, are dragged into the 

* On the action of the pancreatic ferment, see ' A Text-Book 
of Physiology,' by Michael Foster, 2nd edit pp. 198-203. 1878. 

t Schmulewitsch,' Action des Sues digestifs sur la Cellu- 
lose.' Bull, de I'Acad. Imp. de St. Pdtersbourg, torn. xxv. p. 
549- 1879- 



36 HABITS OF WORMS. CHAP. I. 

mouths of their burrows to a depth of from one 
to three inches, and are then moistened with a 
secreted fluid. It has been assumed that this 
fluid serves to hasten their decay ; but a large 
number of leaves were twice pulled out of the 
burrows of worms and kept for many weeks in 
a very moist atmosphere under a bell-glass in 
my study; and the parts which had been 
moistened by the worms did not decay more 
quickly in any plain manner than the other 
parts. When fresh leaves were given in the 
evening to worms kept in confinement and 
examined early on the next morning, therefore 
not many hours after they had been dragged 
into the burrows, the fluid with which they 
were moistened, when tested with neutral 
litmus paper, - showed an alkaline reaction. 
This was repeatedly found to be the case with 
celery, cabbage and turnip leaves. Parts of 
the same leaves which had not been moistened 
by the worms, were pounded with a few drops 
of distilled water, and the juice thus extracted 
was not alkaline. Some leaves, however, which 
had been drawn into burrows out of doors, at 
an unknown antecedent period, were tried, and 
though still moist, they rarely exhibited even a 
trace of alkaline reaction. 



CHAP. I. FOOD AND DIGESTION. 37 

The fluid, with which the leaves are bathed, 
acts on them whilst they are fresh or nearly 
fresh, in a remarkable manner; for it quickly 
kills and discolours them. Thus the ends of 
a fresh carrot-leaf, which had been dragged 
into a burrow, were found after twelve hours 
of a dark brown tint. Leaves of celery, 
turnip, maple, elm, lime, thin leaves of ivy, 
and occasionally those of the cabbage were 
similarly acted on. The end of a leaf of 
Triticum repens, still attached to a growing 
plant, had been drawn into a burrow, and this 
part was dark brown and dead, whilst the 
rest of the leaf was fresh and green. Several 
leaves of lime and elm removed from burrows 
out of doors were found affected in different 
degrees. The first change appears to be that 
the veins become of a dull reddish-orange. 
The cells with chlorophyll next lose more or 
less completely their green colour, and their 
contents finally become brown. The parts 
thus affected often appeared ahnost black by 
reflected light; but when viewed as a trans- 
parent object under the microscope, minute 
specks of light were transmitted, and this 
was not the case with the unaffected parts of 
the same leaves. These efTects, however, 



38 HABITS OF WORMS. CHAP. I. 

merely show that the secreted fluid is highly 
injurious or poisonous to leaves ; for nearly the 
same effects were produced in from one to two 
days on various kinds of young leaves, not only 
by artificial pancreatic fluid, prepared with or 
without thymol, but quickly by a solution of 
thymol by itself. On one occasion leaves of 
Corylus were much discoloured by being kept 
for eighteen hours in pancreatic fluid, without 
any thymol. With young and tender leaves 
immersion in human saliva during rather warm 
weather, acted in the same manner as the 
pancreatic fluid, but not so quickly. The 
leaves in all these cases often became infiltrated 
with the fluid. 

Large leaves from an ivy plant growing 
on a wall were so tough that they could not 
be gnawed by worms, but after four days 
they were affected in a peculiar manner by 
the secretion poured out of their mouths. The 
upper surfaces of the leaves, over which the 
worms had crawled, as was shown by the dirt 
left on them, were marked in sinuous lines, 
by either a continuous or broken chain of 
whitish and often star-shaped dots, about 
2 mm. in diameter. The appearance thus pre- 
sented was curiously like that of a leaf, into 



CHAP. I. FOOD AND DIGESTION. 39 

which the larva of some minute insect had 
burrowed But my son Francis, after making 
and examining sections, could nowhere find 
that the cell-walls had been broken down or 
that the epidermis had been penetrated. 
When the section passed through the whitish 
dots, the grains of chlorophyll were seen to 
be more or less discoloured, and some of the 
palisade and mesophyll cells contained nothing 
but broken down granular matter. These effects 
must be attributed to the transudation of the 
secretion through the epidermis into the cells. 

The secretion with which worms moisten 
leaves likewise acts on the starch*granules 
within the cells. My son examined some 
leaves of the ash and many of the lime, 
which had fallen off the trees and had been 
partly dragged into worm-burrows. It is 
known that with fallen leaves the starch-grains 
are preserved in the guard-cells of the stomata. 
Now in several cases the starch had partially 
or wholly disappeared from the&e cells, in the 
parts which had been moistened by the secre- 
tion; while it was still well preserved in the 
other parts of the same leaves. Sometimes 
the starch was dissolved out of only one of 
the two guard-cells. The nucleus in one case 



40 HABITS OF WORMS. CHAP. L 

had disappeared, together with the starch- 
granules. The mere burjring of lime-leaves 
in damp earth for nine days did not cause the 
destruction of the starch-granules. On the 
other hand, the immersidti of fresh lime and 
cherry leaves for eighteen hours in artificial 
pancreatic fluid, led to the dissolution of the 
starch-granules in the guard-cells as well as in 
the other cells. 

From the secretion with which the leaves 
are moistened being alkaline, and from its 
acting both on the starch-granules and on 
the protoplasmic contents of the cells, we may 
infer that it resembles in nature not saliva,* 
but pancreatic secretion; and we know from 
Fredericq that a secretion of this kind is found 
in the intestines of worms. As the leaves 
which are dragged into the burrows are often 
dry and shrivelled, it is indispensable for their 
disintegration by the unarmed mouths of worms 
that they should first be moistened and softened ; 
and fresh leaves, however soft and tender 
they may be, are similarly treated, probably 
from habit The result is that they are 
partially digested before they are taken into the 

* ClaparMe doubts whether saliva is secreted by worms : 
see 'Zeitschrilt fiir wissenschaft. Zoologie,' B. xix. 1869, p. 601. 



CHAP. I. CALCIFEkOUS GLANDS. 4 1 

alimentary canal. I am not aware of any other 
case of extra-stomachal digestion having been 
recorded The boa-constrictor is said to bathe 
its prey with saliva, but this is doubtful ; and 
it is done solely for the sake of lubricating 
its prey. Perhaps the nearest analogy may be 
found in such plants as Drosera and Dionaea ; 
for here animal matter is digested and con- 
verted into peptone not within a stomach, but 
on the surfaces of the leaves. 

Calci/eraiis Glands. — These glands (see 

rich supply of blood-vessels, must be of much 
importance to the animal. But almost as 
many theories have been advanced on their 
use as there have been observers. They 
consist of three pairs, which in the common 
earth-worm debouch into the alimentary canal 
in advance of the gizzard, but posteriorly to 
it in Urochsta and some other genera.* The 
two posterior pairs are formed by lamellae, 
which, according to ClaparMe, are diverticula 
from the cesophagus.f These lamellae are 
coated with a pulpy cellular layer, with the 

* Peirier, 'Archives de Zodog. exp^r/ July, 1874, PP« 416, 
419- 

t 'Zeitschrift lUr wissenschaft. Zoologie,' B. xix. 1869, pp. 
603-606. 



42 HABITS OF WORMS. CHAP. 1. 

outer cells lying free in infinite numbers. 
If one of these glands is punctured and 
squeezed, a quantity of white pulpy matter 
exudes, consisting of these free cells* They 
are minute, and vary in diameter from 2 to 
6 fu They contain in their centres a little 
excessively fine granular matter ; but they look 
so like oil globules that ClaparMe and others 
at first treated them with ether. This produces 
no effect; but they are quickly dissolved 
with effervescence in acetic acid, and when 
oxalate of ammonia is added to the solution 
a white precipitate b thrown down. We may 
therefore conclude that they contain carbonate 
of lime. If the cells are immersed in a very 
little acid, they become more transparent, look 
like ghosts, and are soon lost to view ; but if 
much acid is added, they disappear instantly. 
After a very large number have been dissolved, 
a flocculent residue is left, which apparently 
consists of the delicate ruptured cell-walls. In 
the two posterior pairs of glands the carbonate 
of lime contained in the cells occasionally 
aggregates into small rhombic crystals or into 
concretions, which lie between the lamellae ; 
but I have seen only one case, and ClaparMe 
only a very few such cases. 



CHAP. I. CALCIFEROUS GLANDS. 43 

The two anterior glands differ a little in 
shape from the four posterior ones, by being 
more oval. They differ also conspicuously in 
generally containing several small, or two or 
three larger, or a single very large concretion 
of carbonate of lime, as much as i^ mm. in 
diameter. When a gland includes only a 
few very small concretions, or, as sometimes 
happens, none at all, it is easily overlooked. 
The large concretions are round or oval, and 
exteriorly almost smooth. One was found 
which filled up not only the whole gland, as 
is often the case, but its neck ; so that it 
resembled an olive-oil flask in shape. These 
concretions when broken are seen to be more 
or less crystalline in structure. How they 
escape from the gland is a marvel ; but that 
they do escape is certain, for they are often 
found in the gizzard, intestines, and in the 
castings of worms, both with those kept in 
confinement and those in a state of nature. 

ClaparMe says very little about the 
structure of the two anterior glands, and he 
supposes that the calcareous matter of which 
the concretions are formed is derived from 
the four posterior glands. But if an anterior 
gland which contains only small concretions 



44 HABITS OF WORMS. CHAP. I. 

is placed in acetic acid and afterwards dis- 
sected, or if sections are made of such a gland 
without being treated with acid, lamella like 
those in the posterior glands and coated with 
cellular matter could be plainly seen, together 
with a multitude of free calciferous cells readily 
soluble in acetic acid. When a gland is com- 
pletely filled with a single large concretion, 
there are no free cells, as these have been all 
consumed in forming the concretion. But if 
such a concretion, or one of only moderately 
large size, is dissolved in acid, much membra- 
nous matter is left, which appears to consist of 
the remains of the formerly active lamellae. 
After the formation and expulsion of a large 
concretion, new lamellae must be developed in 
some manner. In one section made by my 
son, the process had apparently commenced, 
although the gland contained two rather large 
concretions, for near the walls several cylin- 
drical and oval pipes were intersected, which 
were lined with cellular matter and were quite 
filled with free calciferous cells. A great en- 
largement in one direction of several oval pipes 
would give rise to the lamellae. 

Besides the free calciferous cells in which 
no nucleus was visible, other and rather larger 



CHAP. I. CALCIFEROUS GLANDS. 45 

free cells were seen on three occasions ; and 
these contained a distinct nucleus and nucle- 
olus. They were only so far acted on by 
acetic acid that the nucleus was thus rendered 
more distinct A very small concretion was 
removed from between two of the lamellae 
within an anterior gland. It was imbedded in 
pulpy cellular matter, with many free calcifer- 
ous cells, together with a multitude of the 
larger, free, nucleated cells, and these latter 
cells were not acted on by acetic acid, while 
the former were dissolved. From this and 
other such cases I am led to suspect that the 
calciferous cells are developed from the larger 
nucleated ones ; but how this was effected was 
not ascertained. 

When an anterior gland contains several 
minute concretions, some of these are generally 
angular or crystalline in outline, while the 
greater number are rounded with an irregu- 
lar mulberry-like surface. Calciferous cells 
adhered to many parts of these mulberry-like 
masses, and their gradual disappearance could 
be traced while they still remained attached. 
It was thus evident that the concretions are 
formed from the lime contained within the free 
calciferous cells. As the smaller concretions 



46 HABITS OF WORMS. CHilP. I. 

increase in size, they come into contact and 
unite, thus enclosing the now fundtionless 
lamellae; and by such steps the formation of 
the largest concretions could be followed. 
Why the process regularly takes place in the 
two anterior glands, and only rarely in the 
four posterior glands, is quite unknown. 
Morren says that these glands disappear 
during the winter; and I have seen some 
instances of this fact, and others in which 
either the anterior or posterior glands were 
at this season so shrunk and empty, that 
they could be distinguished only with much 
difficulty. 

With respect to the function of the calci- 
ferous glands, it is probable that they pri- 
marily serve as organs of excretion, and 
secondarily as an aid to digestion. Worms 
consume many fallen leaves ; and it is known 
that lime goes on accumulating in leaves until 
they drop off the parent-plant, instead of being 
re-absorbed into the stem or roots, like various 
other organic and inoiganic substances.* The 
ashes of a leaf of an acacia have been known 
to contain as much as 72 per cent of lime. 
Worms therefore would be liable to become 

* De Vries, ' Landwirth. Jahrbucher,' 1881, p. 11. 



CHAP. 1. CALCIFEROUS GLANDS. 47 

charged with this earth, unless there were 
some special means for its excretion ; and the 
calciferous glands are well adapted for this 
purpose. The worms which live in mould 
close over the chalk, often have their intestines 
filled with this substance, and their castings are 
almost white. Here it is evident that the 
supply of calcareous matter must be super- 
abundant. Nevertheless with several worms 
collected on such a site, the calciferous glands 
contained as many free calciferous cells, and 
fully as many and large concretions, as did the 
glands of worms which lived where there was 
little or no lime; and this indicates that the 
lime is an excretion, and not a secretion 
poured into the alimentary canal for some 
special purpose. 

On the other hand, the following considera- 
tions render it highly probable that the 
carbonate of lime, which is excreted by the 
glands, aids the digestive process under 
ordinary circumstances. Leaves during their 
decay generate an abundance of various kinds 
of acids, which have been grouped together 
under the term of humus acids. We shall 
have to recur to this subject in our fifth 
chapter, and I need here only say that these 



48 HABITS OF WORMS. CHAP. I. 

acids act strongly on carbonate of lime. The 
half-decayed leaves which are swallowed in 
such large quantities by worms would^ there- 
fore, after they have been moistened and 
triturated in the alimentary canal^ be apt to 
produce such acids. And in the case of 
several worms, the contents of the alimentary 
canal were found to be plainly acid, as shown 
by litmus paper. This acidity cannot be 
attributed to the nature of the digestive fluid, 
for pancreatic fluid is alkaline; and we have 
seen that the secretion which is poured out of 
the mouths of worms for the sake of preparing 
the leaves for consumption, is likewise alkaline. 
The acidity can hardly be due to uric acid, as 
the contents of the upper part of the intestine 
were often acid. In one case the contents of 
the gizzard were slightly acid, those of the 
upper intestines being more plainly acid. In 
another case the contents of the pharynx were 
not acid, those of the gizzard doubtfully so, 
while those of the intestine were distinctly acid 
at a distance of 5 cm. below the gizzard. 
Even with the higher herbivorous and 
omnivorous animals, the contents of the large 
intestine are acid. "This, however, is not 
'' caused by any acid secretion from the mucous 



i 



CHAP. I. CALCIFEROUS GLANDS. 49 

*' membrane ; the reaction of the intestinal 
'' walls in the larger as in the small intestine is 
"alkaline. It must therefore arise from acid 
'' fermentations going on in the contents them- 

" selves. In Camivora the contents 

*' of the coecum are said to be alkaline, 
''and naturally the amount of fermentation 
^'will depend largely on the nature of the 
•'food/'* 

With worms not only the contents of the 
intestines^ but their ejected matter or the 
castings, are generally acid. Thirty castings 
from different places were tested, and with 
three or four exceptions were found to be 
acid ; and the exceptions may have been due 
to such castings not having been recently 
ejected; for some which were at first acid, 
were on the following morning, after being 
dried and again moistened, no longer acid; 
and this probably resulted from the humus 
acids being, as is known to be the case, easily 
decomposed. Five fresh castings from worms 
which lived in mould close over the chalk, 
were of a whitish colour and abounded with 
calcareous matter; and these were not in 

* M. Foster, < A Text-Book of Phyaology,' 2nd edit. 1878, 
p. 243. 

B 



50 HABITS OF WORMS. CHAP. I. 

the least acid. This shows how effectually 
carbonate of lime neutralises the intestinal 
acids. When worms were kept in pots filled 
with fine ferruginous sand^ it was manifest 
that the oxide of iron^ with which the grains 
of silex were coated, had been dissolved and 
removed from them in the castings. 

The digestive fluid of worms resembles in 
its action, as already stated, the pancreatic 
secretion of the higher animals ; and in these 
latter, ''pancreatic digestion is essentially 
" alkaline ; the action will not take place 
'' unless some alkali be present ; and the 
"activity of an alkaline juice is arrested by 
"acidification, and hindered by neutraliza- 
" tion." • Therefore it seems highly probable 
that the innumerable calciferous cells, which 
are poured from the four posterior glands 
into the alimentary canal of worms, serve to 
neutralise more or less completely the acids 
there generated by the half-decayed leaves. 
We have seen that these cells are instantly 
dissolved by a small quantity of acetic acid, 
and as they do not always suffice to neutralise 
the contents of even the upper part of the 
alimentary canal, the lime is perhaps aggregated 

* M. Foster, ut sup. p. 200. 



CHAP. I. CALCIFEROUS GLANDS. $1 

into concretions in the anterior pair of glands, 
in order that some may be carried down 
to the posterior parts of the intestine, where 
these concretions would be rolled about 
amongst the acid contents. The concretions 
found in the intestines and in the castings 
often have a worn appearance, but whether 
this is due to some amount of attrition or of 
chemical corrosion could not be told. Cla- 
parede believes that they are formed for the 
sake of acting as mill-stones, and of thus 
aiding in the trituration of the food. They 
may give some aid in this way ; but I fully 
agree with Perrier that this must be of quite 
subordinate importance, seeing that the object 
is already attained by stones being generally 
present in the gizzards and intestines of 
worms. 



53 HABITS OF WORMS. CHAP. 11. 



CHAPTER II. 
HABITS OF vfOKUS— continued. 

Manner in which worms seize objects— Their power of suction 
— ^The instinct of plugging up the mouths of their burrows 
— Stones piled over the burrows — ^The advantages thus 
gained— Intelligence shown by worms in their manner of 
plugging up their burrows— Various kinds of leaves and 
other objects thus used — ^Triangles of paper — Summary of 
reasons for believing that worms exhibit some intelligence — 
Meansby which they excavate their burrows, by pushing away 
the earth and swallowingiit— Earth also swallowed for the 
nutritious matter which it contains— Depth to which worms 
burrow, and the construction of their burrows — Burrows 
lined with castings, and in the upper part with leaves — ^The 
lowest part paved with little stones or seeds — Manner in 
which the castings are ejected— The collapse of old burrows 
— Distribution of worms — ^Tower-like castings in Bengal — 
Gigantic castings on the Nilgiri Mountains — Castings 
ejected in all countries. 

In the pots in which worms were kept, leaves 
were pinned down to the soil, and at night 
the manner in which they were seized could 
be observed. The worms always endeavoured 
to drag the leaves towards their burrows ; and 
they tore or sucked off small fragments, when* 
ever the leaves were sufficiently tender. They 



CHAP. II. THEIR MANNER OF PREHENSION. 53 

generally seized the thin edge of a leaf with 
their mouths, between the projecting upper 
and lower lip; the thick and strong pharynx 
being at the same time, as Perrier remarks, 
pushed forward within their bodies, so as to 
afford a point of resistance for the upper lip. 
In the case of broad flat objects they acted 
in a wholly different manner. The pointed 
anterior extremity of the body, after being 
brought into contact with an object of this 
kind, was drawn within the adjoining rings, 
so that it appeared truncated and became as 
thick as the rest of the body. This part could 
then be seen to swell a little; and this, I 
believe, is due to the pharynx being pushed a 
little forwards. Then by a slight withdrawal 
of the pharynx or by its expansion, a vacuum 
was produced beneath the truncated slimy end 
of the body whilst in contact with the object ; 
and by this means the two adhered firmly 
together.* That under these circumstances a 
vacuum was produced was plainly seen on one 
occasion, when a large worm lying beneath a 
flaccid cabbage leaf tried to drag it away ; for 
the sur£Eu:e of the leaf directly over the end of 

* ClaparMe remarks ('Zeitschrift fur wisaenschaft. Zoolog.' 
B. 19, 1869, p. 602) that the pharynx appears from its structure 
to be adapted for suction. 



54 HABITS OF WORMS. CHAP, 11. 

the worm's body became deeply pitted. On 
another occasion a worm suddenly lost its hold 
on a flat leaf; and the anterior end of the 
body was momentarily seen to be cup-formed. 
Worms can attach themselves to an object 
beneath water in the same manner ; and I saw 
one thus dragging away a submerged slice of 
an onion-bulb. 

The edges of fresh or nearly fresh leaves 
affixed to the ground were often nibbled by 
the worms ; and sometimes the epidermis and 
all the parenchyma on one side was gnawed 
completely away over a considerable space; 
the epidermis alone on the opposite side 
being left quite dean. The veins were never 
touched, and leaves were thus sometimes 
partly converted into skeletons. As worms 
have no teeth and as their mouths consist of 
very soft tissue, it may be presumed that they 
consume by means of suction the edges and 
the parenchyma of fresh leaves, after they 
have been softened by the digestive fluid. 
They cannot attack such strong leaves as 
those of sea-kale or large and thick leaves of 
ivy; though one of the latter after it had 
become rotten was reduced in parts to the 
state of a skeleton. 



chap.il protection of their burrows. 55 

Worms seize leaves and other objects^ not 
only to serve as food, but for plugging up the 
mouths of their burrows; and this is one of 
their strongest instincts. They sometimes 
work so energetically that Mr. D. F. Simpson, 
who has a small walled garden where worms 
abound in Bayswater, informs me that on a 
calm damp evening he there heard so ex- 
traordinary a rustling noise from under a 
tree from which many leaves had fallen, that 
he went out with a light and discovered 
that the noise was caused by many worms 
dntgging the dry leaves and squeezing them 
into the burrows. Not only leaves, but 
petioles of many kinds, some flower-peduncles, 
often decayed twigs of trees, bits of paper, 
feathers, tufts of wool and horse-hairs are 
dragged into their burrows for this purpose. 
I have seen as many as seventeen petioles of 
a Clematis projecting from the mouth of one 
burrow, and ten from the mouth of another. 
Some of these objects, such as the petioles 
just named, feathers, &c., are never gnawed 
by worms. In a gravel- walk in my garden I 
found many hundred leaves of a pine-tree {P. 
austriaca or nigricans) drawn by their bases 
into burrows. The surfaces by which these 



56 HABITS OF WORMS. CHAP. II. 

leaves are articulated to the branches are 
shaped in as peculiar a manner as is the joint 
between the leg-bones of a quadruped ; and if 
these surfaces had been in the least gnawed, 
the fact would have been immediately visible, 
but there was no trace of gnawing. Of ordi- 
nary dicotyledonous leaves, all those which 
are dragged into burrows are not gnawed. I 
have seen as many as nine leaves of the lime- 
tree drawn into the same burrow, and not 
nearly all of them had been gnawed ; but such 
leaves may serve as a store for future con* 
sumption. Where fallen leaves are abundant, 
many more are sometimes collected over the 
mouth of a burrow than can be used, so 
that a small pile of unused leaves is left like 
a roof over those which have been partly 
dragged in. 

A leaf in being dragged a little way into 
a cylindrical burrow is necessarily much folded 
or crumpled. When another leaf is drawn in, 
this is done exteriorly to the first one, and so 
on with the succeeding leaves ; and finally all 
become closely folded and pressed together. 
Sometimes the worm enlarges the mouth of 
its burrow, or makes a fresh one close by, so 
as to draw in a still larger number of leaves. 



CHAP. II. PROTECTION OF THEIR BURROWS. 57 

They often or generally fill up the interstices 
between the drawn-in leaves with moist viscid 
earth ejected from their bodies ; and thus the 
mouths of the burrows are securely plugged. 
Hundreds of such plugged burrows may be 
seen in many places^ especially during the 
autumnal and early winter months. But, as 
will hereafter be shown, leaves are dragged 
into the burrows not only for plugging them 
up and for food, but for the sake of lining the 
upper part or mouth. 

When worms cannot obtain leaves, petioles, 
sticks, &c., with which to plug up the mouths 
of their burrows, they often protect them by 
little heaps of stones ; and such heaps of 
smooth rounded pebbles may frequently be 
seen on gravel-walks. Here there can be no 
question about food. A lady, who was in- 
terested in the habits of worms, removed the 
little heaps of stones from the mouths of 
several burrows and cleared the surface of the 
ground for some inches all round She went 
out on the following night with a lantern, and 
saw the worms with their tails fixed in their 
burrows, dragging the stones inwards by the 
aid of their mouths, no doubt by suction. 
*' After two nights some of the holes had 8 or 



58 HABITS OF WORMS. CHAP. 1 1- 

'^ 9 small stones over them ; after four nights 
''one had about 30, and another 34 stones/' * 
One stone which had been dragged over 
the gravel-walk to the mouth of a burrow 
weighed two ounces; and this proves how 
strong worms are. But they show greater 
strength in sometimes displacing stones in a 
well-trodden gravel-walk; that they do so, 
may be inferred from the cavities left by the 
displaced stones being exactly filled by those 
lying over the mouths of adjoining burrows, 
as I have myself observed. 

Work of this kind is usually performed 
during the night; but I have occasionally 
known objects to be drawn into the burrows 
during the day. What advantage the worms 
derive from plugging up the mouths of their 
burrows with leaves, &a, or from piling stones 
over them, is doubtful. They do not act in 
this manner at the times when they eject much 
earth from their burrows; for their castings 
then serve to cover the mouths. When gar- 
deners wish to kill worms on a lawn, it is 
necessary first to brush or rake away the 
castings from the surface, in order that the 

* An account of her observations is given in the ' Gardeners' 
Chronicle,' March 28th, 1868, p. 324* 



CHAP. II. PROTECTION OF THEIR BURROWS. 59 

lime-water may enter the burrows.* It might 
be inferred from this fact that the mouths are 
plugged up with leaves, &c., to prevent the 
entrance of water during heavy rain; but it 
may be urged against this view that a few, 
loose, well-rounded stones are ill-adapted to 
keep out water. I have moreover seen many 
burrows in the perpendicularly cut turf-edgings 
to gravel-walks» into which water could hardly 
flow, as well plugged as burrows on a level 
surface. It is not probable that the plugs or 
piles of stones serve to conceal the burrows 
from scolopendras, which, according to Hoff- 
meister,f are the bitterest enemies of worms, 
or from the larger species of Carabus and 
Staphylinus which attack them ferociously, for 
these animals are nocturnal, and the burrows 
are opened at night. May not worms when 
the mouth of the burrow is protected be able 
to remain with safety with their heads dose to 
it, which we know that they like to do, but 
which costs so many of them their lives ? Or 
may not the plugs check the free ingress of 
the lowest stratum of air, when chilled by 

* Loudon's ' Gard. Mag.' xviL p. 216, as quoted in the 
' Catalogue of the British Museum Wonns/ 1865, p. 327. 
t * Familie der Regenwiirmer,' p. 19. 



6o HABITS OF WORMS. CHAP. II. 

radiation at night, from the surrounding ground 
and herbage? I am inclined to believe in 
this latter view : firstly, because when worms 
were kept in pots in a room with a fire, in 
which case cold air could not enter the burrows, 
they plugged them up in a slovenly manner ; 
and secondarily, because they often coat the 
upper part of their burrows with leaves, ap- 
parently to prevent their bodies from coming 
into close contact with the cold damp earth. 
Mr. E. Parfitt has suggested to me that the 
mouths of the burrows are closed in order that 
the air within them may be kept thoroughly 
damp, and this seems the most probable ex- 
planation of the habit But the plugging-up 
process may serve for all the above purposes. 

Whatever the motive may be, it appears 
that worms much dislike leaving the mouths 
of their burrows open. Nevertheless they 
wOl reopen them at night, whether or not 
they can afterwards close them. Numerous 
open burrows may be seen on recently-dug 
ground, for in this case the worms eject their 
castings in cavities left in the ground, or in 
the old burrows instead of piling them over 
the mouths of their biurows, and they cannot 
collect objects on the surface by which the 



CHAP. II. THEIR INTELLIGENCE. 6 1 

mouths might be protected. So again on a 
recently disinterred pavement of a Roman 
villa at Abinger (hereafter to be described) 
the worms pertinaciously opened their burrows 
almost every night, when these had been 
closed by being trampled on» although they 
were rarely able to find a few minute stones 
wherewith to protect them. 

Intelligence shown by warms in their manner 
of plugging up their burrows. — If a man had to 
plug up a small cylindrical hole, with such 
objects as leaves, petioles or twigs, he would 
drag or push them in by their pointed ends ; 
but if these objects were very thin relatively 
to the size of the hole, he would probably 
insert some by their thicker or broader ends. 
The guide in his case would be intelligence. 
It seemed therefore worth while to observe 
carefully how worms dragged leaves into their 
burrows; whether by their tips or bases or 
middle parts. It seemed more especially 
desirable to do this in the case of plants not 
natives to our country ; for although the habit 
of dragging leaves into their burrows is un- 
doubtedly instinctive with worms, yet instinct 
could not tell them how to act in the case of 
leaves about which their progenitors knew 



62 HABITS OF WORMS* CHAP. II. 

nothing. If, moreover, worms acted solely 
through instinct or an unvarying inherited 
impulse, they would draw all kinds of leaves 
into their burrows in the same manner. If 
they have no such definite instinct, we might 
expect that chance would determine whether 
the tip, base or middle was seized. If both 
these alternatives are excluded, intelligence 
alone is left; unless the worm in each case 
first tries many different methods, and follows 
that alone which proves possible or the most 
easy; but to act in this manner and to try 
different methods makes a near approach to 
intelligence. 

In the first place 227 withered leaves of 
various kinds, mostly of English plants, were 
pulled out of worm-burrows in several places. 
Of these, 181 had been drawn into the burrows 
by or near their tips, so that the foot-stalk 
projected nearly upright from the mouth of 
the burrow; 20 had been drawn in by their 
bases, and in this case the tips projected from 
the burrows ; and 26 had been seized near the 
middle, so that these had been drawn in trans- 
versely and were much crumpled. Therefore 
80 per cent, (always using the nearest whole 
number) had been drawn in by the tip, 9 per 



CHAP. II. THEIR INTELUGENCE. 63 

cent by the base or foot-stalk, and 1 1 per cent 
transversely or by the middle. This alone is 
almost sufficient to show that chance does not 
determine the manner in which leaves are 
dragged into the burrows. 

Of the above 227 leaves, 70 consisted of 
the fallen leaves of the common lime*tree, 
which is almost certainly not a native of 
England. These leaves are much acuminated 
towards the tip, and are very broad at the base 
with a well-developed foot-stalk. They are 
thin and quite flexible when half-withered. Of 
the 70, 79 per cent had been drawn in by or 
near the tip ; 4 per cent by or near the base ; 
and 17 per cent transversely or by the middle. 
These proportions agree very closely, as far as 
the tip is concerned, with those before given. 
But the percentage drawn in by the base is 
smaller, which may be attributed to the breadth 
of the basal part of the blade. We here, also, 
see that the presence of a foot-stalk, which it 
might have been expected would have tempted 
the worms as a convenient handle, has little or 
no influence in determining the manner in 
which lime leaves are dragged into the burrows. 
The considerable proportion, viz., 17 per cent, 
drawn in more or less transversely depends no 



64 HABITS OF WORMS. CHAP. 11. 

doubt on the flexibility of these half-decayed 
leaves. The fact of so many having been 
drawn « in by the middle, and of some few 
having been drawn in by the base, renders it 
improbable that the worms first tried to draw 
in most of the leaves by one or both of these 
methods, and that they afterwards drew in 79 
per cent by their tips ; for it is clear that they 
would not have failed in drawing them in by 
the base or middle. 

The leaves of a foreign plant were next 
searched for, the blades of which were not 
more pointed towards the apex than towards 
the base. This proved to be the case with 
those of a laburnum (a hybrid between Cytisus 
alpinus and ladumum) for on doubling the 
terminal over the basal half, they generally 
fitted exactly ; and when there was any 
difference, the basal half was a little the 
narrower. It might, therefore, have been 
expected that an almost equal number of 
these leaves would have been drawn in by the 
tip and base, or a slight excess in favour of 
the latter. But of 73 leaves (not included in 
the first lot of 227) pulled out of worm- 
burrows^ 63 per cent, had been drawn in by 
the tip; 27 per cent by the base, and 10 per 



CHAP. II. THEIR INTELLIGENCE. 65 

cent, transversely. We here see that a far 
larger proportion, viz., 27 per cent were 
drawn in by the base than in the case of 
lime leaves, the blades of which are very 
broad at the base, and of which only 4 per 
cent, had thus been drawn in. We may 
perhaps account for the fact of a still larger 
proportion of the laburnum leaves not having 
been drawn in by the base, by worms having 
acquired the habit of generally drawing in 
leaves by their tips and thus avoiding the foot- 
stalk. For the basal margin of the blade in 
many kinds of leaves forms a large angle with 
the foot-stalk ; and if such a leaf were drawn 
in by the foot-stalk, the basal margin would 
come abruptly into contact with the ground on 
each side of the burrow, and would render the 
drawing in of the leaf very difficult. 

Nevertheless worms break through their 
habit of avoiding the foot-stalk, if this part 
offers them the most convenient means for 
drawing leaves into their burrows. The leaves 
of the endless hybridised varieties of the Rho- 
dodendron vary much in shape; some are 
narrowest towards the base and others towards 
the apex. After they have fallen off, the blade 
on each side of the midrib often becomes curled 



66 HABITS OF WORMS. CHAP. II. 

up while drying, sometimes along the whole 
length, sometimes chiefly at the base, some- 
times towards the apex. Out of 28 fallen 
leaves on one bed of peat in my garden, no 
less than 23 were narrower in the basal quarter 
than in the terminal quarter of their length ; 
and this narrowness was chiefly due to the 
curling in of the margins. Out of 36 fallen 
leaves on another bed, in which different varie- 
ties of the Rhododendron grew, only 1 7 were 
narrower towards the base than towards the 
apex. My son William, who first called my 
attention to this case, picked up 237 fallen 
leaves in his garden (where the Rhododendron 
grows in the natural soil) and of these 65 per 
cent could have been drawn by worms into 
their burrows more easily by the base or foot- 
stalk than by the tip ; and this was partly due 
to the shape of the leaf and in a less degree to 
the curling in of the margins : 27 per cent 
could have been drawn in more easily by the 
tip than by the base : and 8 per cent with 
about equal ease by either end. The shape of 
a fallen leaf ought to be judged of before one 
end has been drawn into a burrow, for after 
this has happened, the free end, whether it be 
the base or apex, will dry more quickly than the 



CHAF.II. THEIR INTELLIGBNCB. 67 

end imbedded in the damp ground ; and the ex- 
posed mai^ns of the free end will consequently 
tend to become more curled inwards than they 
were when the leaf was first seized by the 
worm. My son found 91 leaves which had been 
dragged by worms into their burrows^ though 
not to a great depth ; of these 66 per cent had 
been drawn in by the base or foot-stalk ; and 
34 per cent by the tip. In this case, therefore, 
the worms judged with a considerable degree 
of correctness how best to draw the withered 
leaves of this foreign plant into their burrows ; 
notwithstanding that they had to depart from 
their usual habit of avoiding the foot-stalk. 

On the gravd-walks in my garden a very 
large number of leaves of three species of 
Pinus (P. OMstriaca, nigricans and sylvestris) 
are regularly drawn into the mouths of worm- 
burrows. These leaves consist of two so- 
called needles, which are of considerable length 
in the two first and short in the last named 
species, and are united to a common base ; and 
it is by this part that they are almost invariably 
drawn into the burrows. I have seen only 
two or at most three exceptions to this rule 
with worms in a state of nature. As the 
sharply pointed needles diverge a little, and as 



68 HABITS OF WORMS. CHAP. II. 

several leaves are drawn into the same burrow, 
each tuft forms a perfect chevaux de/rtse. On 
two occasions many of these tufts were pulled 
up in the evening, but by the following morning 
fresh leaves had been pulled in, and the 
burrows were again well protected. These 
leaves could not be dragged into the burrows 
to any depth, except by their bases, as a worm 
cannot seize hold of the two needles at the 
same time, and if one alone were seized by 
the apex, the other would be pressed against 
the ground and would resist the entry of the 
seized one. This was manifest in the above 
mentioned two or three exceptional cases. In 
order, therefore, that worms should do their 
work well, they must drag pine-leaves into 
their burrows by their bases, where the two 
needles are conjoined. But how they are 
guided in this work is a perplexing question. 

This difficulty led my son Francis and my- 
self to observe worms in confinement during 
several nights by the aid of a dim light, while 
they dragged the leaves of the above named 
pines into their burrows. They moved the 
anterior extremities of their bodies about the 
leaves, and on several occasions when they 
touched the sharp end of a needle they 



CHAP. ir. THEIR INTELLIGENCE. 69 

withdrew suddenly as if pricked But I doubt 
whether they were hurt^ for they are indifferent 
to very sharp objects, and will swallow even 
rose-thorns and small splinters of glass. It 
may also be doubted, whether the sharp ends 
of the needles serve to tell them that this is 
the wrong end to seize; for the points were 
cut oiT many leaves for a length of about one 
inch, and fifty-seven of them thus treated were 
drawn into the burrows by their bases, and not 
one by the cut-off ends. The worms in con- 
finement often seized the needles near the 
middle and drew them towards the mouths of 
their burrows ; and one worm tried in a sense- 
less manner to drag them into the burrow 
by bending them. They sometimes collected 
many more leaves over the mouths of their 
burrows (as in the case formerly mentioned of 
lime-leaves) than could enter them. On other 
occasions, however, they behaved very dif- 
ferently ; for as soon as they touched the base 
of a pine-leaf, this was seized, being some- 
times completely engulfed in their mouths, or 
a point v^ near the base was seized, and the 
leaf was then quickly dragged or rather jerked 
into their burrows. It appeared both to my 
son and myself as if the worms instantly 



70 HABITS OF WORMS. CHAP. II. 

perceived as soon as they had seized a leaf in 
the proper manner. Nine such cases were 
observedi but in one of them the worm failed 
to drag the leaf into its burrow, as it was 
entangled by other leaves lying near. In 
another case a leaf stood nearly upright with 
the points of the needles partly inserted into a 
burroWi but how placed there was not seen; 
and then the worm reared itself up and seized 
the base, which was dragged into the mouth 
of the burrow by bowing the whole leaf. On 
the other hand, after a worm had seized the 
base of a leaf, this was on two occasions relin- 
quished from some unknown motive. 

As already remarked, the habit of plugging 
up the mouths of the burrows with various 
objects, is no doubt instinctive in worms ; and 
a very young one, born in one of my pots, 
dragged for some little distance a Scotch-fir 
leaf, one needle of which was as long and 
almost as thick as its own body. No species 
of pine is endemic in this part of England, it 
is therefore incredible that the proper manner 
of dragging pine-leaves into the burrows can 
be instinctive with our worms. But as the 
worms on which the above observations were 
made, were dug up beneath or near some 



CHAP.U. THEIR INTELLIGENCE. ^l 

pines, which had been planted there about 
forty years, it was desirable to prove that their 
actions were not instinctive. Accordingly, 
pine-leaves were scattered on the ground in 
places far removed from any pine-tree, and 90 
of them were drawn into the burrows by their 
bases. Only two were drawn in by the tips of 
the needles, and these were not real exceptions, 
as one was drawn in for a very short distance, 
and the two needles of the other cohered. 
Other pine-leaves were given to worms kept 
in pots in a warm room, and here the result 
was different ; for out of 42 leaves drawn into 
the burrows, no less than 16 were drawn in by 
the tips of the needles. These worms, how- 
ever, worked in a careless or slovenly manner ; 
for the leaves were often drawn in to only a 
small depth; sometimes they were merely 
heaped over the mouths of the burrows, and 
sometimes none were drawn in. I believe 
that this carelessness may be accounted for 
either by the warmth of the air, or by its 
dampness, as the pots were covered by glass 
plates; the worms consequently did not care 
about plugging up their holes effectually. Pots 
tenanted by worms and covered with a net 
which allowed the free entrance of air, were 



72 HABITS OF WORMS. CHAP. II. 

left out of doors for several nights, and now 
72 leaves were all properly drawn in by their 
bases. 

It might perhaps be inferred from the facts 
as yet given, that worms somehow gain a 
general notion of the shape or structure of 
pine-leaveS| and perceive that it is necessary 
for them to seize the base where the two 
needles are conjoined. But the following 
cases make this more than doubtful. The 
tips of a large number of needles of P. austriaca 
were cemented together with shell-lac dis- 
solved in alcohol, and were kept for some 
days, until, as I believe, all odour or taste had 
been lost; and they were then scattered on 
the ground where no pine-trees grew, near 
burrows from which the plugging had been 
removed. Such leaves could have been drawn 
into the burrows with equal ease by either 
end ; and judging from analogy and more 
especially from the case presently to be given 
of the petioles of Clematis montana, I expected 
that the apex would have been preferred. But 
the result was that out of 121 leaves with the 
tips cemented, which were drawn into burrows, 
K)8 were drawn in by their bases, and only 13 
by their tips. Thinking that the worms might 



CHAP. II. THEIR INTELLIGENCE. 73 

possibly perceive and dislike the smell or 
taste of the shell-lac, though this was very 
improbable, especially after the leaves had been 
left out during several nights, the tips of the 
needles of many leaves were tied together 
with fine thread. Of leaves thus treated 150 
were drawn into burrows — 123 by the base 
and 27 by the tied tips; so that between four 
and five times as many were drawn in by the 
base as by the tip. It is possible that the 
short cut-off ends of the thread with which 
they were tied, may have tempted the worms 
to drag in a larger proportional number by the 
tips than when cement was used. Of the 
leaves with tied and cemented tips taken 
together (271 in number) 85 per cent, were 
drawn in by the base and 15 per cent, by the 
tips. We may therefore infer that it is not 
the divergence of the two needles which leads 
worms in a state of nature almost invariably 
to drag pine-leaves into their burrows by the 
base. Nor can it be the sharpness of the 
points of the needles which determines them ; 
for, as we have seen, many leaves with the 
points cut off were drawn in by their bases. 
We are thus led to conclude, that with pine- 
leaves there must be something attractive to 



74 HABITS OP WORMS. CHAP. IL 

worms in the base, notwithstanding that few 
ordinary leaves are drawn in by the base or 
foot-stalk. 

Petioles. — ^We will now turn to the petioles 
or foot-stalks of compound leaves, after the 
leaflets have fallen off. Those from Clematis 
mantana^ which grew over a verandah, were 
dragged early in January in large numbers 
into the burrows on an adjoining gravel- 
walk, lawn, and flower-bed. These petioles 
vary from 2^ to 4^ inches in length, are rigid 
and of nearly uniform thickness, except dose 
to the base where they thicken rather abruptly, 
being here about twice as thick as in any other 
part The apex is somewhat pointed, but 
soon withers and is then easily broken off. 
Of these petioles, 314 were pulled out of 
burrows in the above specified sites; and it 
was found that 76 per cent, had been drawn 
in by their tips, and 24 per cent by their 
bases ; so that those drawn in by the tip were 
a little more than thrice as many as those 
drawn in by the base. Some of those extracted 
from the well-beaten gravel-walk were kept 
separate from the others ; and of these (59 in 
number) nearly five times as many had been 
drawn in by the tip as by the base ; whereas 



CHAP. II. THBIR INTELLIGENCE. 75 

of those extracted from the lawn and flower- 
bed, where from the soil yielding more easily, 
less care would be necessary in plugging up 
the burrows, the proportion of those drawn in 
by the tip (130) to those drawn in by the base 
(48) was rather less than three to one. That 
these petioles had been dragged into the 
burrows for plugging them up, and not for 
food, was manifest, as neither end, as far as I 
could see, had been gnawed. As several 
petioles are used to plug up the same burrow, 
in one case as many as 10, and in another case 
as many as 15, the worms may perhaps at first 
draw in a few by the thicker end so as to save 
labour; but afterwards a large majority are 
drawn m by the pointed end, in order to plug 
up the hole securdy. 

The fallen petioles of our native ash-tree 
were next observed, and the rule with most 
objects, viz., that a large majority are dragged 
into the burrows by the more pointed end, had 
not here been followed; and diis fact much 
surprised me at first. These petioles vary in 
length from 5 to 8^ inches ; they are thick 
and fleshy towards the base, whence they taper 
gently towards the apex, which is a little en- 
larged and truncated where the terminal leaflet 



76 HABITS OF WORMS. CHAP. II. 

had been originally attached. Under some 
ash-trees growing in a grass-field, 229 petioles 
were pulled out of worm burrows early in 
January, and of these 51-5 per cent had been 
drawn in by the base, and 48*5 per cent by 
the apex. This anomaly was however readily 
explained as soon as the thick basal part was 
examined; for in 78 out of 103 petioles, this 
part had been gnawed by worms, just above 
the horse-shoe shaped articulation. In most 
cases there could be no mistake about the 
gnawing; for ungnawed petioles which were 
examined after being exposed to the weather 
for eight additional weeks had not become 
more disintegrated or decayed near the base 
than elsewhere. It is thus evident that the 
thick basal end of the petiole is drawn in not 
solely for the sake of plugging up the mouths 
of the burrows, but as food. Even the narrow 
truncated tips of some few petioles had been 
gnawed; and this was the case in 6 out of 
^j which were examined for this purpose. 
Worms, after having drawn in and gnawed 
the basal end, (^ten push the petioles out of 
their burrows; and then drag in fresh ones, 
either by the base for food, or by the apex 
for plugging up the mouth more effectually. 



CHAF.II. THEIR INTELLIGENCE. 77 

Thus, out of 37 petioles inserted by their 
tips, 5 had been previously drawn in by the 
base, for this part had been gnawed. Again, 
I collected a handful of petioles lying loose 
on the ground dose to some plugged-up bur* 
rows, where the surface was thickly strewed 
with other petioles which apparently had never 
been touched by worms; and 14 out of 47 
{t.e. nearly one-third), after having had their 
bases gnawed had been pushed out of the 
burrows and were now lying on the ground 
From these several facts we may conclude 
that worms draw in some petioles of the ash 
by the base to serve as food, and others by 
the tip to plug up the mouths of their burrows 
in the most efficient manner. 

The petioles of Robinia pseudo-acacia vary 
from 4 or 5 to nearly 12 inches in length; 
they are thick close to the base before the 
softer parts have rotted off, and taper much 
towards the upper end. They are so flexible 
that I have seen some few doubled up and 
thus drawn into the burrows of worms. Un- 
fortunately these petioles were not examined 
until February, by which time the softer parts 
had completely rotted off, so that it was im- 
possible to ascertain whether worms had 



78 HABITS OF WORMS* CHAP. II. 

gnawed the bases, though this is in itself 
probable. Out of 121 petioles extracted from 
burrows early in February, 68 were imbedded 
by the base, and 53 by the apex. On Feb- 
ruary 5 all the petioles which had been drawn 
into the burrows beneath a Robinia, were 
pulled up; and after an interval of eleven 
days» 35 petioles had been again dragged in, 
19 by the base, and t6 by the apex. Taking 
these two lots together, 56 per cent were 
drawn in by the base, and 44 per cent by 
the apex* As all the softer parts had long 
ago rotted off, we may feel sure, especially in 
the latter case, that none had been drawn in 
as food. At this season, therefore, worms drag 
these petioles into their burrows indifferently 
by either end, a slight preference being given 
to the base. This latter fact may be accounted 
for by the difficulty of plugging up a burrow 
with objects so extremely thin as are the 
upper ends. In support of this view, it may 
be stated that out of the 16 petioles which 
had been drawn in by their upper ends, the 
more attenuated terminal portion of 7 had 
been previously broken off by some accident 

Triangles of paper. — Elongated triangles 
were cut out of moderately stiff writing-paper, 



CHAP. II. THEIR INTELLIGENCE. 79 

which was rubbed with raw fat on both sides, 
so as to prevent their becoming excessively 
limp when exposed at night to rain and dew. 
The sides of all the triangles were three 
inches in length, with the bases of 120 one 
inch, and of the other 183 half an inch in 
length. These latter triangles were very 
narrow or much acuminated.* As a check 
on the observations presently to be given, 
similar triangles in a damp state were seized 
by a very narrow pair of pincers at different 
points and at all inclinations with reference 
to the margins, and were then drawn into 
a short tube of the diameter of a worm- 
burrow. If seized by the apex, the triangle 
was drawn straight into the tube, with its 
margins infolded; if seized at some little 
distance from the apex^ for instance at half 
an inch, this much was doubled back within 
the tube. So it was with the base and basal 
angles, though in this case the triangles 
offered, as might have been expected, much 
more resistance to being drawn in. If seized 
near the middle the triangle was doubled up, 

* In these narrow triangles the apical angle is 9^ 34', and 
the basal angles 85^ 13'. In the broader triangles the apical 
angle is 19^ 10' and the basal angles 80^ 25'. 



80 HABITS OF WORMS. CHAP. II. 

with the apex and base left sticking out of the 
tube. As the sides of the triangles were 
three inches in length, the result of their 
being drawn into a tube or into a burrow in 
different ways, may be conveniently divided 
into three groups: those drawn in by the 
apex or within an inch of it ; those drawn in 
by the base or within an inch of it ; and those 
drawn in by any point in the middle inch. 

In order to see how the triangles would be 
seized by worms, some in a damp state were 
given to worms kept in confinement. They 
were seized in three different manners in the 
case of both the narrow and broad triangles : 
viz., by the margin; by one of the three 
angles, which was often completely engulfed 
in their mouths ; and lastly, by suction applied 
to any part of the flat surface. If lines 
parallel to the base and an inch apart, are 
drawn across a triangle with the sides three 
inches in length, it will be divided into three 
parts of equal length. Now if worms seized 
indifferently by chance any part, they would 
assuredly seize on the basal part or division 
far oftener than on either of the two other 
divisions. For the area of the basal to the 
apical part is as 5 to i, so that the chance 



CHAP. II. THEIR INTELLIGENCE. 8 1 

of the former being drawn into a burrow by 
suction, will be as 5 to i, compared with the 
apical part The base offers two angles and 
the apex only one, so that the former would 
have twice as good a chance (independently 
of the size of the angles) of being engulfed 
in a worm's mouth, as would the apex. It 
should, however, be stated that the apical 
angle is not often seized by worms; the 
margin at a little distance on either side 
being preferred. I judge of this from having 
found in 40 out of 46 cases in which triangles 
had been drawn into burrows by their apical 
ends, that the tip had been doubled back 
within the burrow for a length of between 
^th of an inch and i inch. Lastly, the pro- 
portion between the margins of the basal and 
apical parts is as 3 to 2 for the broad, and 
2^ to 2 for the narrow triangles. From these 
several considerations it might certainly have 
been expected, supposing that worms seized 
hold of the triangles by chance, that a con* 
siderably larger proportion would have been 
dragged into the burrows by the basal than by 
the apical part ; but we shall immediately see 
how different was the result. 

Triangles of the above specified sizes were 

G 



82 HABITS OF WORMS. CHAP. II. 

scattered on the ground in many places and 
on many successive nights near worm-burrows, 
from which the leaves, petioles, twigs, &c., 
with which they had been plugged, were 
removed. Altogether 303 triangles were 
drawn by worms into their burrows: 12 
others were drawn in by both ends, but as it 
was impossible to judge by which end they 
had been first seized, these are excluded. Of 
the 303, 62 per cent had been drawn in by 
the apex (using this term for all drawn in by 
the apical part, one inch in length); 15 per 
cent, by the middle ; and 23 per cent, by the 
basal part. If they had been drawn in- 
differently by any point, the proportion for 
the apical, middle and basal parts would have 
been 33*3 per cent, for each ; but, as we have 
just seen, it might have been expected that a 
much larger proportion would have been 
drawn in by the basal than by any other part. 
As the case stands, nearly three times as many 
were drawn in by the apex as by the base. If 
we consider the broad triangles by themselves, 
59 per cent, were drawn in by the apex, 25 per 
cent by the middle, and 16 per cent by the 
base. Of the narrow triangles, 65 per cent, 
were drawn in by the apex, 14 per cent by the 



CHAP. II. THEIR INTELLIGENCE. 83 

middle, and 21 per cent, by the base ; so that 
here those drawn in by the apex were more 
than 3 times as many as those drawn in by the 
base. We may therefore conclude that the 
manner in which the triangles are drawn into 
the burrows is not a matter of chance. 

In eight cases, two triangles had been 
drawn into the same burrow, and in seven of 
these cases, one had been drawn in by the apex 
and the other by the base. This again indi- 
cates that the result is not determined by 
chance. Worms appear sometimes to revolve 
in the act of drawing in the triangles, for five 
out of the whole lot had been wound into an 
irregular spire round the inside of the burrow. 
Worms kept in a warm room drew 63 triangles 
into their burrows ; but, as in the case of the 
pine-leaves, they worked in a rather careless 
manner, for only 44 per cent, were drawn in by 
the apex, 22 per cent by the middle, and 33 
per cent by the base. In five cases, two 
triangles were drawn into the same burrow. 

It may be suggested with much apparent 
probability that so large a proportion of the 
triangles were drawn in by the apex, not from 
the worms having selected this end as the 
most convenient for the purpose, but from 



84 HABITS OF WORMS. CHAP. II. 

having first tried in other ways and failed. 
This notion was countenanced by the manner 
in which worms in confinement were seen to 
drag about and drop the triangles; but then 
they were working carelessly. I did not at 
first perceive the importance of this subject, 
but merely noticed that the bases of those tri- 
angles which had been drawn in by the apex, 
were generally clean and not crumpled. The 
subject was afterwards attended to carefully. 
In the first place several triangles which had 
been drawn in by the basal angles, or by the 
base, or a little above the base, and which 
were thus much crumpled and dirtied, were 
left for some hours in water and were then 
well shaken while immersed ; but neither the 
dirt nor the creases were thus removed. Only 
slight creases could be obliterated, even by 
pulling the wet triangles several times through 
my fingers. Owing to the slime from the 
worms' bodies, the dirt was not easily washed 
off. We may therefore conclude that if a 
triangle, before being dragged in by the apex, 
had been dragged into a burrow by its base 
with even a slight degree of force, the basal 
part would long retain its creases and remain 
dirty. The condition of 89 triangles (65 



CHAP. 11. THEIR INTELLIGENCE. 85 

narrow and 24 broad ones), which had been 
drawn in by the apex, was observed ; and the 
bases of only 7 of them were at all creased, 
being at the same time generally dirty. Of 
the 82 uncreased triangles, 14 were dirty at the 
base ; but it does not follow from this fact that 
these had first been dragged towards the bur- 
rows by their bases ; for the worms sometimes 
covered large portions of the triangles with 
slime, and these when dragged by the apex 
over the ground would be dirtied ; and during 
rainy weather, the triangles were often dirtied 
over one whole side or over both sides. If 
the worms had dragged the triangles to the 
mouths of their burrows by their bases, as 
often as by their apices, and had then per- 
ceived, without actually trying to draw them 
into the burrow, that the broader end was not 
well adapted for this purpose— even in this 
case a large proportion would probably have 
had their basal ends dirtied. We may there- 
fore infer — improbable as is the inference — 
that worms are able by some means to judge 
which is the best end by which to draw 
triangles of paper into their burrows. 

The percentage results of the foregoing 
observations on the manner in which worms 



86 



HABITS OF WORMS. 



CHAP. II. 



draw various kinds of objects into the mouths 
of their burrows may be abridged as follows :— 



Nun* of Object. 



Leaves of various kinds • • • . 

of the Lime, basal margin of 

blade broad, apex acuminated . 

of a Laburnum, basal part of 

blade as narrow as, or some- 
times little narrower than the 
apical part • • • . 

of the Rhododendron, basal part 

of blade often narrower than 
the apical part . 

of Pine-trees, consisting of two 

needles arising from a common 
base ••••«• 

Petioles of a Qematis, somewhat pointed 
at the apex, and blunt at the 
base • • « • • 

of the Ash, the thick basal end 

often drawn in to serve as 
food 

of Robinia, extremely thin, espe- 
cially towards the apex, so as 
to be ill-fitted for. plugging up 
the burrows • . . • 

Triangles of paper, of the two sizes . 

of the broad ones alone • 

— —— of the narrow ones alone . 



Drawn 
intotha 
barrows. 



by or 
near the 



80 



79 



63 



34 



76 



48-5 



44 
62 

S9 
65 



Drawn 

in, by or 
neartbie 
middle. 



II 



17 



10 



Drawn 
in, by or 
irtbt 



IS 

as 
14 



27 



66 



100 



SI'S 



56 

23 
16 

21 



If we consider these several cases, we can 
hardly escape from the conclusion that worms 



CHAP. II. THEIR INTELUGENCE. 87 

show some degree of intelligence in their 
manner of plugging up their burrows. Each 
particular object is seized in too uniform a 
manner, and from causes which we can 
generally understand, for the result to be 
attributed to mere chance. That every object 
has not been drawn in by its pointed end, may 
be accounted for by labour having been saved 
through some being inserted by their broader 
or thicker ends. No doubt worms are led by 
instinct to plug up their burrows ; and it might 
have been expected that they would have been 
led by instinct how best to act in each par* 
ticular case, independently of intelligence. We 
see how difficult it is to judge whether in- 
telligence comes into play, for even plants 
might sometimes be thought to be thus 
directed; for instance when displaced leaves 
re-direct their upper surfaces towards the light 
by extremely complicated movements and by 
the shortest course. With animals, actions 
appearing due to intelligence may be per- 
formed through inherited habit without any 
intelligence, although aboriginally thus ac- 
quired. Or the habit may have been acquired 
through the preservation and inheritance of 
beneficial variations of some other habit; and 



88 HABITS OF WORMS. CHAP. IL 

in this case the new habit will have been 
acquired independently of intelligence through- 
out the whole course of its development 
There is no ^ priori improbability in worms 
having acquired special instincts through either 
of these two latter means. Nevertheless it 
is incredible that instincts should have been 
developed in reference to objects, such as the 
leaves of petioles of foreign plants, wholly 
unknown to the progenitors of the worms 
which act in the described manner. Nor are 
their actions so unvarying or inevitable as 
are most true instincts. 

As worms are not guided by special in- 
stincts in each particular case, though pos- 
sessing a general instinct to plug up their 
burrows, and as chance is excluded, the next 
most probable conclusion seems to be that 
they try in many different ways to draw in 
objects, and at last succeed in some one way. 
But it is surprising that an animal so low in 
the scale as a worm should have the capacity 
for acting in this manner, as many higher 
animals have no such capacity. For instance, 
ants may be seen vainly trying to drag an 
object transversely to their course, which could 
be easily drawn longitudinally; though after 



CHilP. II. THEIR INTELLIGENCE. 89 

a time they generally act in a wiser manner. 
M. Fabre states* that a Sphex— an insect 
belonging to the same highly-endowed order 
with ants — stocks its nest with paralyzed grass- 
hoppersi which are invariably dragged into the 
burrow by their antennae. When these were 
cut off close to the head, the Sphex seized the 
palpi; but when these were likewise cut off, 
the attempt to drag its prey into the burrow 
was given up in despair. The Sphex had 
not intelligence enough to seize one of the 
six legs or the ovipositor of the grasshopper, 
which, as M. Fabre remarks, would have 
served equally well So again, if the paralyzed 
prey with an egg attached to it be taken out 
of the cell, the Sphex after entering and 
finding the cell empty, nevertheless closes it 
up in the usual elaborate manner. Bees will 
try to escape and go on buzzing for hours on 
a window, one half of which has been left 
open. Even a pike continued during three 
months to dash and bruise itself against the 
glass sides of an aquarium, in the vain attempt 
to seize minnows on the opposite side.t A 

^ See his interesting work, 'Souvenirs entomologiques,' 
1879, pp. 168-177. 

t MObius, ' Die Bewegungen der Thiere,* &c., 1873, p. iii. 



90 HABITS OF WORMS. CHAP. II. 

cobra-snake was seen by Mr. Layard* to 
act much more wisely than either the pike 
or the Sphex ; it had swallowed a toad lying 
within a hole, and could not withdraw its head ; 
the toad was disgorged, and began to crawl 
away ; it was again swallowed and again dis- 
gorged; and now the snake had learnt by 
experience, for it seized the toad by one of 
its legs and drew it out of the hole. The 
instincts of even the higher animals are often 
followed in a senseless or purposeless manner : 
the weaver-bird will perseveringly wind threads 
through the bars of its cage, as if building a 
nest : a squirrel will pat nuts on a wooden 
floor, as if he had just buried them in the 
ground : a beaver will cut up logs of wood 
and drag them about, though there is no 
water to dam up ; and so in many other cases. 
Mr. Romanes, who has specially studied 
the minds of animals, believes that we can 
safely infer intelligence, only when we see an 
individual profiting by its own experience. 
By this test the cobra showed some intelli- 
gence ; but this would have been much plainer 
if on a second occasion he had drawn a toad 

* * Annab and Mag. of N. History/ series ii. voL iz. 1852, 
P- 333- 



CHAP. II. THEIR INTELLIGENCE. 9 1 

out of a hole by its 1^. The Sphex failed 
signally in this respect Now if worms try 
to drag objects into their burrows first in one 
way and then in another, until they at last 
succeed, they profit, at least in each particular 
instance, by experience. 

But evidence has been advanced showing 
that worms do not habitually try to draw 
objects into their burrows in many different 
ways. Thus half-decayed lime-leaves from 
thek flexibility could have been drawn in by 
their middle or basal parts, and were thus 
drawn into the burrows in considerable 
numbers; yet a large majority were drawn 
in by or near the apex. The petioles of the 
Clematis could certainly have been drawn in 
with equal ease by the base and apex; yet 
three times and in certain cases five times as 
many were drawn in by the apex as by the 
base. It might have been thought that the 
foot-stalks of leaves would have tempted 
the worms as a convenient handle; yet they 
are not largely used, except when the base of 
the blade is narrower than the apex. A large 
number of the petioles of the ash are drawn 
in by the base ; but this part serves the worms 
as food. In the case of pineJeaves worms 



92 HABITS OF WORMS. CHAP. 11. 

plainly show that they at least do not seize 
the leaf by chance ; but their choice does not 
appear to be determined by the divergence of 
the two needles, and the consequent advantage 
or necessity of drawing them into their burrows 
by the base. With respect to the triangles 
of paper, those which had been drawn in by 
the apex rarely had their bases creased or 
dirty ; and this shows that the worms had not 
often first tried to drag them in by this end. 

If worms are able to judge, either before 
drawing or after having drawn an object close 
to the mouths of their burrows, how best to 
drag it in, they must acquire some notion of 
its general shape. This they probably acquire 
by touching it in many places with the anterior 
extremity of their bodies, which serves as a 
tactile organ. It may be well to remember 
how perfect the sense of touch becomes in a 
man when bom blind and deaf, as are worms. 
If worms have the power of acquiring some 
notion, however rude, of the shape of an object 
and of their burrows, as seems to be the case, 
they deserve to be called intelligent ; for they 
then act in nearly the same manner as would 
a man under similar circumstances. 

To sum up, as chance does not determine 



chap.il excavation of their burrows. 93 

the manner in which objects are drawn into 
the burrows, and as the existence of specialized 
instincts for each particular case cannot be 
admitted, the first and most natural supposition 
is that worms try all methods until they at last 
succeed; but many appearances are opposed 
to such a supposition. One alternative alone 
is left, namely, that worms, although standing 
low in the scale of organization, possess some 
degree of intelligence. This will strike every 
one as very improbable; but it may be 
doubted whether we know enough about the 
nervous system of the lower animals to justify 
our natural distrust of such a conclusion* With 
respect to the small size of the cerebral ganglia, 
we should remember what a mass of inherited 
knowledge, with some power of adapting 
means to an end, is crowded into the minute 
brain of a worker-ant. 

Means by which worms excavate their 
burrows. — This is effected in two ways; by 
pushing away the earth on all sides, and by 
swallowing it In the former case, the worm 
inserts the stretched out and attenuated 
anterior extremity of its body into any little 
crevice, or hole ; and then, as Perrier remarks,* 

* ' Archives de Zoolog. exp^r.' torn. iii. 1874, p. 405. 



94 HABITS OF WORMS. CHAP. II. 

the pharynx is pushed forwards into this part, 
which consequently swells and pushes away 
the earth on all sides. The anterior extremity 
thus serves as a wedge. It also serves^ as we 
have before seen, for prehension and suction, 
and as a tactile organ. A worm was placed 
on loose mould, stnd it buried itself in between 
two and three minutes. On another occasion 
four worms disappeared in 15 minutes between 
the sides of the pot and the earth, which had 
been moderately pressed down. On a third 
occasion three large worms and a small one 
were placed on loose mould well mixed with 
fine sand and firmly pressed down, and they 
all disappeared, except the tail of one, in 35 
minutes. On a fourth occasion six large 
worms were placed on argillaceous mud mixed 
with sand firmly pressed down, and they dis- 
appeared, except the extreme tips of the tails 
of two of them, in 40 minutes. In none of 
these cases, did the worms swallow, as far as 
could be seen, any earth. They generally 
entered the ground close to the sides of the 
pot 

A pot was next filled with very fine ferru- 
ginous sand, which was pressed down, well 
watered, and thus rendered extremely compact 



CHilP.U. EXCAVATION OF THEIR BURROWS. 95 

A large worm left on the surface did not 
succeed in penetrating it for some hours, and 
did not bury itself completely until 25 hrs. 
40 min. had elapsed. This was effected by 
the sand being swallowed, as was evident by 
the large quantity ejected from the vent, long 
before the whole body had disappeared. Cast- 
ings of a similar nature continued to be ejected 
from the burrow during the whole of the 
following day. 

As doubts have been expressed by some 
writers whether worms ever swallow earth 
solely for the sake of making their burrows, 
some additional cases may be given* A mass 
of fine reddish sand, 23 inches in thickness, 
left on the ground for nearly two years, had 
been penetrated in many places by worms; 
and their castings consisted partly of the 
reddish sand and partly of black earth brought 
up from beneath the mass. This sand had 
been dug up from a considerable depth, and 
was of so poor a nature that weeds could not 
grow on it It is therefore highly improbable 
that it should have been swallowed by the 
worms as food. Again in a field near my 
house the castings frequently consist of almost 
pure chalk, which lies at only a little depth 



96 HABITS OF WORMS. CHAP. II. 

beneath the surface ; and here again it is very 
improbable that the chalk should have been 
swallowed for the sake of the very little 
organic matter which could have percolated 
into it from the poor overlying pasture. 
Lastly, a casting thrown up through the con- 
crete and decayed mortar between the tiles, 
with which the now ruined aisle of Beaulieu 
Abbey had formerly been paved, was washed, 
so that the coarser matter alone was left. 
This consisted of grains of quartz, micaceous 
slate, other rocks, and bricks or tiles, many 
of them from sV to i^ inch in diameter. No 
one will suppose that these grains were swal- 
lowed as food, yet they formed more than 
half of the casting, for they weighed 19 grains, 
the whole casting having weighed 33 grains. 
Whenever a worm burrows to a depth of 
some feet in undisturbed compact ground, it 
must form its passage by swallowing the earth ; 
for it is incredible that the ground could yield 
on all sides to the pressure of the pharynx 
when pushed forwards within the worm's 
body. 

That worms swallow a larger quantity of 
earth for the sake of extracting any nutritious 
matter which it may contain than for making 



CHAP. II. EARTH SWALLOWED AS FOOD. 97 

their burrows, appears to me certain. But as 
this old belief has been doubted by so high 
an authority as Clapar&de, evidence in its 
favour must be given in some detail. There 
is no d priori improbability in such a belief, 
for besides other annelids, especially the 
Arenicola marina^ which throws up such a 
profusion of castings on our tidal sands, and 
which it is believed thus subsists, there are 
animals belonging to the most distinct classes, 
which do not burrow, but habitually swallow 
large quantities of sand ; namely, the molluscan 
Onchidium and many Echinoderms.* 

If earth were swallowed only when worms 
deepened their burrows or made new ones, 
castings would be thrown up only occasionally ; 
but in many places fresh castings may be seen 
every morning, and the amount of earth ejected 
from the same burrow on successive days is 
large. Yet worms do not burrow to a great 
depth, except when the weather is very dry 
or intensely cold. On my lawn the black 
vegetable mould or humus is only about 5 
inches in thickness, and overlies light-coloured 
or reddish clayey soil : now when castings are 

* I state this on the authority of Semper, * Reisen im Archipel 
der Philippinen,' Th. ii. 1877, p. 3a 

H 



98 HABITS OF WORMS. CHAP. II. 

thrown up in the greatest profusion, only a 
small proportion are light coloured, and it is 
incredible that the worms should daily make 
fresh burrows in every direction in the thin 
superficial layer of dark-coloured mould, unless 
they obtained nutriment of some kind from 
it. I have observed a strictly analogous case 
in a field near my house where bright red 
clay lay close beneath the surface. Again on 
one part of the Downs near Winchester the 
vegetable mould overlying the chalk was found 
to be only from 3 to 4 inches in thickness; 
and the many castings here ejected were as 
black as ink and did not effervesce with acids ; 
so that the worms must have confined them* 
selves to this thin superficial layer of mould, 
of which large quantities were daily swallowed. 
In another place at no great distance the cast- 
ings were white ; and why the worms should 
have burrowed into the chalk in some places 
and not in others, I am unable to conjecture. 

Two great piles of leaves had been left to 
decay in my grounds, and months after their 
removal, the bare surface, several yards in 
diameter, was so thickly covered during several 
months with castings that they formed an 
almost continuous layer ; and the large number 



chap.il earth swallowed as food. 99 

of worms which lived here must have subsisted 
during these months on nutritious matter con* 
tained in the black earth. 

The lowest layer from another pile of 
decayed leaves mixed with some earth was 
examined under a high power, and the number 
of spores of various shapes and sizes which 
it contained was astonishingly great; and 
these crushed in the gizzards of worms may 
largely aid in supporting them. Whenever 
castings are thrown up in the greatest number, 
few or no leaves are drawn into the burrows ; 
for instance the turf along a hedgerow, about 
200 yards in length, was daily observed in the 
autumn during several weeks, and every morn- 
ing many fresh castings were seen; but not 
a single leaf was drawn into these burrows. 
These castings from their blackness and from 
the nature of the subsoil could not have been 
brought up from a greater depth than 6 or 8 
inches. On what could these worms have sub< 
sisted during this whole time, if not on matter 
contained in the black earth ? On the other 
hand, whenever a large number of leaves are 
drawn into the burrows, the worms seem to 
subsist chiefly on them, for few earth-cast- 
ings are then ejected on the surface. This 



482flf)ftA 



lOO HABITS OF WORMS. CHAP. II. 

difference in the behaviour of worms at different 
times, perhaps explains a statement by Clapa- 
r^de, namely, that triturated leaves and earth 
are always found in dbtinct parts of their 
intestines. 

Worms sometimes abound in places where 
they can rarely or never obtain dead or living 
leaves ; for instance, beneath the pavement in 
well-swept courtyards, into which leaves are 
only occasionally blown. My son Horace 
examined a house, one comer of which had 
subsided ; and he found here in the cellar, 
which was extremely damp, many small worm- 
castings thrown up between the stones with 
which the cellar was paved ; and in this case 
it is improbable that the worms could ever 
have obtained leaves. Mr. A. C. Horner 
confirms this account, as he has seen castings 
in the cellars of his house, which is an old one 
at Tonbridge. 

But the best evidence, known to me, of 
worms subsisting for at least considerable 
periods of time solely on the organic matter 
contained in earth, is afforded by some facts 
communicated to me by Dr. King. Near 
Nice large castings abound in extraordinary 
numbers, so that 5 or 6 were often found 



CHAP. 11. EARTH SWALLOWED AS FOOD. lOI 

within the space of a square foot They 
consist of fine, pale-coloured earth, containing 
calcareous matter, which after having passed 
through the bodies of worms and being dried, 
coheres with considerable force. I have 
reason to believe that these castings had been 
formed by species of Perichaeta, which have 
been naturalized here from the East* They 
rise like towers, with their summits often a 
little broader than their bases, sometimes to 
a height of above 3 and often to a height of 
2^ inches. The tallest of those which were 
measured was 3*3 inches in height and i inch 
in diameter. A small cylindrical passage runs 
up the centre of each tower, through which 
the worm ascends to eject the earth which it 
has swallowed, and thus to add to its height. 
A structure of this kind would not allow leaves 

* Dr. King gave me some worms collected near Nice, which, 
as he bdieves, had constructed these castings. They were sent 
to M. Perrier, who with great kindness examined and named 
them for me : they consisted of Pirkhata affims^ a native of 
Cochin Qiina and of the Philipinnes ; P. Lus^niea^ a native of 
Lazon in the Philippines ; and P. HoulUH^ which lives near 
CalCQtta* M. Perrier informs me that species of Perichaeta 
have been naturalised in the gardens near MontpeUier and in 
Algiers. Before I had any reason to suspect that the tower- 
like castings from Nice had been formed by worms not endemic 
in the country, I was greatly surprised to see how closely they 
resembled castings sent to me from near Calcutta, where it is 
known that species of Perichaeta abound. 



I02 HABITS OF WORMS. CHAP. II. 

being easily dragged from the surrounding 
ground into the burrows ; and Dr. King, who 
looked carefully, never saw even a fragment 
of a leaf thus drawn in. Nor could any trace 
be discovered of the worms having crawled 
down the exterior surfaces of the towers in 
search of leaves ; and had they done so, tracks 
would almost certainly have been left on the 
upper part whilst it remained soft It does 
not, however, follow that these worms do not 
draw leaves into their burrows during some 
other season of the year, at which time they 
would not build up their towers. 

From the several foregoing cases, it can 
hardly be doubted that worms swallow earth, 
not only for the sake of making their burrows, 
but for obtaining food. Hensen, however, 
concludes from his analyses of mould that 
worms probably could not live on ordinary 
vegetable mould, though he admits that they 
might be nourished to some extent by leaf- 
mould.* But we have seen that worms eagerly 
devour raw meat, fat, and dead worms; and 
ordinary mould can hardly fail to contain 
many ova, larvse, and small living or dead 

* 'Zeitschrift fur wissenschaft Zoolog.' B. xxviii. 1877, 
p. 364- 



CHAR II. DEPTH OF THEIR BURROWS. IO3 

creatures, spores of cryptc^^amic plants, and 
micrococci, such as those which give rise to 
saltpetre. These various organisms, together 
with some cellulose from any leaves and roots 
not utterly decayed, might well account for 
such large quantities of mould being swallowed 
by worms. It may be worth while here to 
recall the fact that certain species of Utricularia, 
which grow in damp places in the tropics^ 
possess bladders beautifully constructed for 
catching minute subterranean animals; and 
these traps would not have been developed 
unless many small animals inhabited such soil. 
The depth to which warms penetrate, and 
the construction of their burrows. — Although 
worms usually live near the surface, yet they 
burrow to a considerable depth during long- 
continued dry weather and severe cold. In 
Scandinavia, according to Eisen, and in Scot- 
land, according to Mr. Lindsay Camagie, the 
burrows run down to a depth of from 7 to 8 
feet ; in North Germany, according to Hoff- 
meister, from 6 to 8 feet, but Hensen says, 
from 3 to 6 feet. This latter observer has seen 
worms frozen at a depth oi \\ feet beneath 
the surface. I have not myself had many 
opportunities for observation, but I have often 



I04 HABITS OF WORMS. CHAP. II. 

met with worms at depths of 3 to 4 feet. 
In a bed of fine sand overlying the chalk, 
which had never been disturbed, a worm was 
cut into two at 55 inches, and another was 
found here at Down in December at the 
bottom of its burrow, at 61 inches beneath the 
surface. Lastly, in earth near an old Roman 
Villa, which had not been disturbed for many 
centuries, a worm was met with at a depth of 66 
inches ; and this was in the middle of August 

The burrows run down perpendicularly, or 
more commonly a little obliquely. They are 
said sometimes to branch, but as far as I have 
seen this does not occur, except in recently 
dug ground and near the surface. They are 
generally, or as I believe invariably, lined 
with a thin layer of fine, dark-coloured earth 
voided by the worms; so that they must at 
first be made a little wider than their ultimate 
diameter. I have seen several burrows in 
undisturbed sand thus lined at a depth of 4 ft 
6 in. ; and others close to the surface thus 
lined in recently dug ground. The walls of 
fresh burrows are often dotted with little 
globular pellets of voided earth, still soft and 
viscid ; and these, as it appears, are spread out 
on all sides by the worm as it travels up or 



CHAP. II. CONSTRUCTION OF THEIR BURROWS. IDS 

down its burrow. The lining thus formed 
becomes very compact and smooth when 
nearly dry, and closely fits the worm's body. 
The minute reflexed bristles which project in 
rows on all sides from the body, thus have 
excellent points of support ; and the burrow 
is rendered well adapted for the rapid move- 
ment of the animal. The lining appears also 
to strengthen the walls, and perhaps saves the 
worm's body from being scratched. I think 
so because several burrows which passed 
through a layer of sifted coal-cinders, spread 
over turf to a thickness of i^^ inch, had been 
thus lined to an unusual thickness. In this 
case the worms, judging from the castings, 
had pushed the cinders away on all sides and 
had not swallowed any of them. In another 
place, burrows similarly lined, passed through 
a layer of coarse coal-cinders, 3^^ inches in 
thickness. We thus see that the burrows are 
not mere excavations, but may rather be 
compared with tunnels lined with cement 

The mouths of the burrow are in addition 
often lined with leaves ; and this is an instinct 
distinct from that of plugging them up, and 
does not appear to have been hitherto noticed. 
Many leaves of the Scotch-fir or pine {Pinus 



I06 HABITS OF WORMS. CHAP. II. 

sylvestris) were given to worms kept in confine- 
ment in two pots; and when after several 
weeks the earth was carefully broken up, the 
upper parts of three oblique burrows were 
found surrounded for lengths of 7, 4, and 
3^ inches with pine-leaves, together with frag- 
ments of other leaves which had been given 
the worms as food. Glass beads and bits of 
tile, which had been strewed on the surface 
of the soili were stuck into the interstices 
between the pine-leaves ; and these interstices 
were likewise plastered with the viscid castings 
voided by the worms. The structures thus 
formed cohered so well, that I succeeded in 
removing one with only a little earth adhering 
to it It consisted of a slightly curved cylin- 
drical case, the interior of which could be 
seen through holes in the sides and at either 
end. The pine-leaves had all been drawn in 
by their bases ; and the sharp points of the 
needles had been pressed into the lining of 
voided earth. Had this not been effectually 
done, the sharp points would have prevented 
the retreat of the worms into their burrows ; 
and these structures would have resembled 
traps armed with converging points of wire, 
rendering the ingress of an animal easy and 



CHAP. II. CONSTRUCTION OF THEIR BURROWS. IO7 

its egress difficult or impossible. The skill 
shown by these worms is noteworthy and is 
the more remarkable, as the Scotch pine is not 
a native of this district 

After having examined these burrows made 
by worms in confinement, I looked at those in 
a flower-bed near some Scotch pines. These 
had all been plugged up in the ordinary manner 
with the leaves of this tree, drawn in for a 
length of from i to it^ inch ; but the mouths of 
many of them were likewise lined with them, 
mingled with fragments of other kinds of 
leaves, drawn in to a depth of 4 or 5 inches. 
Worms often remain, as formerly stated, for a 
long time close to the mouths of their burrows, 
apparently for warmth; and the basket-like 
structures formed of leaves would keep their 
bodies from coming into close contact with the 
cold damp earth. That they habitually rested 
on the pine-leaves, was rendered probable by 
their clean and almost polished surfaces. 

The burrows which run far down into the 
ground, generally, or at least often, terminate 
in a little enlargement or chamber. Here, 
according to HofTmeister, one or several worms 
pass the winter rolled up into a ball. Mr. 
Lindsay Carnagie informed me (1838) that he 



I08 HABITS OF WORMS. CHAP. II. 

had examined many burrows over a stone- 
quarry in Scotland, where the overlying 
boulder-day and mould had recently been 
cleared away, and a little vertical cliff thus left 
In several cases the same burrow was a little 
enlarged at two or three points one beneath 
the other ; and all the burrows terminated in a 
rather large chamber, at a depth of 7 or 8 feet 
from the surface. These chambers contained 
many small sharp bits of stone and husks of 
flax-seeds. They must also have contained 
living seeds, for on the following spring Mr. 
Camagie saw grass-plants sprouting out of 
some of the intersected chambers. I found at 
Abinger in Surrey two burrows terminating in 
similar chambers at a depth of 36 and 41 
inches, and these were lined or paved with 
little pebbles, about as large as mustard seeds ; 
and in one of the chambers there was a decayed 
oat-grain, with its husk. Hensen likewise 
states that the bottoms of the burrows are 
lined with little stones; and where these 
could not be procured, seeds, apparently of 
the pear, had been used, as many as fifteen 
having been carried down into a single burrow, 
one of which had germinated.* We thus see 

* ' 2^itschrift fur wissenschaft. Zoolog.' B. xxviii. 1877, p. 356. 



CHAP.n. EJECTION OF THEIR CASTINGS. IO9 

how easily a botanist might be deceived who 
wished to learn how long deeply buried seeds 
remained alive, if he were to collect earth from 
a considerable depth, on the supposition that 
it could contain only seeds which had long lain 
buried. It is probable that the little stones, as 
well as the seeds, are carried down from the 
surface by being swallowed ; for a surprising 
number of glass beads, bits of tile and of glass 
were certainly thus carried down by worms 
kept in pots ; but some may have been carried 
down within their mouths. The sole con- 
jecture which I can form why worms line their 
winter-quarters with little stones and seeds, is 
to prevent their closely coiled*up bodies from 
coming into close contact with the surrounding 
cold soil; and such contact would perhaps 
interfere with their respiration which is effected 
by the skin alone. 

A worm after swallowing earth, whether 
for making its burrow or for food, soon comes 
to the surface to empty its body. The ejected 
earth is thoroughly mingled with the intestinal 
secretions, and is thus rendered viscid. After 
being dried it sets hard. I have watched 
worms during the act of ejection, and when the 
earth was in a very liquid state it was ejected 



no HABITS OF WORMS. CHAP. 11. 

in little spurts, and by a slow peristaltic move- 
ment when not so liquid. It is not cast 
indifferently on any side, but with some care, 
first on one and then on another side ; the tail 
being used almost like a troweL When a 
worm comes to the surface to eject earth, the 
tail protrudes, but when it collects leaves its 
head must protrude. Worms therefore must 
have the power of turning round in their 
closely-fitting burrows ; and this, as it appears 
to us, would be a difficult feat As soon as 
a little heap has been formed, the worm 
apparently avoids, for the sake of safety, pro- 
truding its tail; and the earthy matter is 
forced up through the previously deposited 
soft mass. The mouth of the same burrow 
is used for this purpose for a considerable 
time. In the case of the tower-like castings 
(see Fig. 2) near Nice, and of the similar but 
still taller towers from Bengal (hereafter to be 
described and figured), a considerable degree 
of skill is exhibited in their construction. 
Dr. King also observed that the passage up 
these towers hardly ever ran in the same exact 
line with the underlying burrow, so that a thin 
cylindrical object such as a haulm of grass, 
could not be passed down the tower into the 



CHAP. II. THE COLLAPSE OF OLD BURROWS. Ill 

burrow ; and this change of direction probably 
serves in some manner as a protection. 

Worms do not always eject their castings 
on the surface of the ground. When they can 
find any cavity, as when burrowing in newly 
turned-up earthy or between the stems of 
banked-up plants, they deposit their castings 
in such places. So again any hollow beneath 
a large stone lying on the surface of the 
ground, is soon filled up with their castings. 
According to Hensen, old burrows are habitu- 
ally used for this purpose ; but as far as my 
experience serves^ this is not the case, except- 
ing with those near the surface in recently dug 
ground. I think that Hensen may have been 
deceived by the walls of old burrows, lined with 
black earth, having sunk in or collapsed ; for 
black streaks are thus left, and these are con- 
spicuous when passing through light-coloured 
soil, and might be mistaken for completely 
fiUed-up burrows. 

It is certain that old burrows collapse in 
the course of time ; for as we shall see in the 
next chapter, the fine earth voided by worms, 
if spread out uniformly, would form in many 
places in the course of a year a layer i of an 
inch in thickness ; so that at any rate this large 



112 HABITS OF WORMS. CHAP. II. 

amount is not deposited within the old unused 
burrows. If the burrows did not collapse, the 
whole ground would be first thickly riddled 
with holes to a depth of about ten inches, and 
in fifty years a hollow unsupported space, ten 
inches in depth, would be left The holes left 
by the decay of successively formed roots of 
trees and plants must likewise collapse in the 
course of time. 

The burrows of worms run down perpen- 
dicularly or a little obliquely, and where the 
soil is at all argillaceous, there is no difficulty 
in believing that the walls would slowly flow 
or slide inwards during very wet weather. 
When, however, the soil is sandy or mingled 
with many small stones, it can hardly be 
viscous enough to flow inwards during even 
the wettest weather ; but another agency may 
here come into play. After much rain the 
ground swells, and as it cannot expand later- 
ally, the surface rises; during dry weather 
it sinks again. For instance, a large flat 
stone laid on the surface of a field sank 
3*33 mm. whilst the weather was dry between 
May 9th and June 13th, and rose 1*91 mm. 
between September 7th and 19th of the same 
year, much rain having fallen during the latter 



CHAP. II. THEIR WIDE DISTRIBUTION. II3 

part of this time. During frosts and thaws 
the movements were twice as great These 
observations were made by my son Horace, 
who will hereafter publish an account of the 
movements of this stone during successive 
wet and dry seasons, and of the effects of its 
being undermined by worms* Now when the 
ground swells, if it be penetrated by cylindrical 
holes, such as worm-burrows, their walls will 
tend to yield and be pressed inwards ; and the 
yielding will be greater in the deeper parts 
(supposing the whole to be equally moistened) 
from the greater weight of the superincumbent 
soil which has to be raised, than in the parts 
near the surface. When the ground dries, the 
walls will shrink a little and the burrows will 
be a little enlarged Their enlargement, how- 
ever, through the lateral contraction of the 
ground, will not be favoured, but rather op- 
posed, by the weight of the superincumbent 
soil. 

Dislributian of Worms. — Earth-worms are 
found in all parts of the world, and some of 
the genera have an enormous range.* They 
inhabit the most bolated islands ; they abound 
in Iceland, and are known to exist in the 

♦ Pcrricr, * Archives dc Zoolog. exp^r.' torn. 3, p. 378, 1874. 

I 



114 HABITS OF WORMS. CHAP. II. 

West Indies, St. Helena, Madagascar, New 
Caledonia and Tahiti. In the Antarctic re- 
gions, worms from Kerguelen Land have been 
described by Ray Lankester; and I found 
them in the Falkland Islands. How they 
reach such isolated islands is at present quite 
unknown. They are easily killed by salt- 
water, and it does not appear probable that 
young worms or their egg-capsules could be 
carried in earth adhering to the feet or beaks 
of land-birds. Moreover Kerguelen Land is 
not now inhabited by any land-bird. 

In this volume we are chiefly concerned 
with the earth cast up by worms, and I have 
gleaned a few facts on this subject with respect 
to dbtant lands. Worms throw up plenty of 
castings in the United States. In Venezuela, 
castings, probably ejected by species of Uro- 
chseta, are common in the gardens and fields, 
but not in the forests, as I hear from Dr. Ernst 
of Caracas. He collected 156 castings from 
the court-yard of his house, having an area 
of 200 square yards. They varied in bulk 
from half a cubic centimeter to five cubic 
centimeters, and were on an average three 
cubic centimeters. They were, therefore, of 
small size in comparison with those often 



chap.il their wide distribution. 115 

found in England ; for six large castings from 
a field near my house averaged 16 cubic centi- 
meters. Several species of earth-worms are 
common in St. Catharina in South Brazil, and 
Fritz Mttller informs me '' that in most parts of 
" the forests and pasture-lands, the whole soil, 
'' to a depth of a quarter of a metre, looks as if 
"it had passed repeatedly through the intes« 
" tines of earth-worms, even where hardly any 
'' castings are to be seen on the surface." A 
gigantic but very rare species is found there, 
the burrows of which are sometimes even two 
centimeters or nearly | of an inch in diameter, 
and which apparently penetrate the ground 
to a great depth. 

In the dry climate of New South Wales, I 
hardly expected that worms would be common ; 
but Dr. G. Krefft of Sydney, to whom I 
applied, after making inquiries from gardeners 
and others, and from his own observations, 
informs me that their castings abound. He 
sent me some collected after heavy rain, and 
they consisted of little pellets, about '15 inch 
in diameter; and the blackened sandy earth 
of which they were formed still cohered with 
considerable tenacity. 

The late Mr. John Scott of the Botanic 



Il6 HABITS OF WORMS. CHAP. II. 

Gardens near Calcutta made many observa* 
tions for me on worms living under the hot 
and humid climate of Bengal The castings 
abound almost everywhere, in jungles and in 
the open ground, to a greater degree, as he 
thinks, than in England. After the water has 
subsided from the flooded rice-fields, the whole 
surface very soon becomes studded with cast- 
ings — a fact which much surprised Mr. Scott, 
as he did not know how long worms could 
survive beneath water. They cause much 
trouble in the Botanic garden, ^'for some of 
*' the finest of our lawns can be kept in any- 
'' thing like order only by being almost daily 
''rolled; if left undisturbed for a few days 
''they become studded with large castings.'' 
These closely resemble those described as 
abounding near Nice; and they are probably 
the work of a species of Perichseta. They 
stand up like towers, with an open passage in 
the centre. 

A figure of one of these castings from a 
photograph is here given (Fig. 3). The largest 
received by me was 3^ inches in height an4 
1*35 inch in diameter ; another was only i inch 
in diameter and 2} in height. In the following 
year, Mr. Scott measured several of the largest ; 




.S2 



^1 

2S 



51 



1-1 




CHAP. II. THEIR WIDE DISTRIBUTION. II7 

one was 6 inches in height and nearly i^ in 
diameter : two others were 5 inches in height 
and respectively 2 and rather more than 2^^ 
inches in diameter. The average weight of 
the 22 castings sent to me was 35 grammes 
(li oz.); and one of them weighed 44*8 
grammes (or 2 oz.). All these castings were 
thrown up either in one night or in two. 
Where the ground in Bengal is dry, as under 
large trees, castings of a different kind are 
found in vast numbers : these consist of little 
oval or conical bodies, from about the ^ to 
rather above ^ of an inch in length. They 
are obviously voided by a distinct species of 
worms. 

The period during which worms near 
Calcutta display such extraordinary activity 
lasts for only a little over two months, namely, 
during the cool season after the rains. At thb 
time they are generally found within about 10 
inches beneath the surface. During the hot 
season they burrow to a greater depth, and are 
then found coiled up and apparently hyber- 
nating. Mr. Scott has never seen them at a 
greater depth than 2| feet, but has heard of 
their having been found at 4 feet. Within 
the forests, fresh castings may be found even 



Il8 HABITS OF WORMS. CHAP. II. 

during the hot season. The worms in the 
Botanic garden, during the cool and dry season, 
draw many leaves and little sticks into the 
mouths of their burrows, like our English 
worms; but they rarely act in this manner 
during the rainy season. 

Mr. Scott saw worm-castings on the lofty 
mountains of Sikkim in North India. In 
South India Dr. King found in one place, 
on the plateau of the Nilgiris, at an elevation 
of 7000 feet, "a good many castings," which 
are interesting for their great size. The worms 
which eject them are seen only during the wet 
season, and are reported to be from 12 to 15 
inches in length, and as thick as a man's little 
finger. These castings were collected by Dr. 
King after a period of 1 10 days without any 
rain ; and they must have been ejected either 
during the north-east or more probably during 
the previous south-west monsoon; for their 
sur&ces had suffered some disintegration and 
they were penetrated by many fine roots. A 
drawing is here given (Fig. 4) of one which 
seems to have best retained its original size 
and appearance. Notwithstanding some loss 
from disintegration, five of the largest of these 
castings (after having been well sun-dried) 



chap.il their wide distribution. 119 

weighed each on an average 89*5 grammes, 
or above 3 oz. ; and the largest weighed 123*14 
grammes, or 4^ oz., — that is, above a quarter 
of a pound! The lai^est convolutions were 
rather more than one inch in diameter ; but it 
is probable that they had subsided a little whilst 
soft, and that their diameters had thus been 
increased. Some had flowed so much that 
they now consisted of a pile of almost flat 
confluent cakes. All were formed of fine, 
rather light-coloured earth, and were surpris- 
ingly hard and compact, owing no doubt to 
the animal matter by which the particles of 
earth had been cemented together. They 
did not disintegrate, even when left for some 
hours in water. Although they had been 
cast up on the surface of gravelly soil, 
they contained extremely few bits of rock, 
the largest of which was only '15 inch in 
diameter. 

Dr. King saw in Ceylon a worm about 2 
feet in length and ^ inch in diameter; and 
he was told that it was a very common species 
during the wet season. These worms must 
throw up castings at least as large as those 
on the Nilgiri Mountains; but Dr. King 
saw none during his short ^isit to Ceylon. 



I20 HABITS OF WORMS. CHAP. II. 

Sufficient facts have now been given, showing 
that worms do much work in bringing up 
fine earth to the surface in most or all parts 
of the worldi and under the most different 
climates. 



( 121 ) 



CHAPTER III. 

THE AMOUNT OF FINE EARTH BROUGHT UP BY 
WORMS TO THE SURFACE. 

Rate at which various objects strewed on the surface of grass- 
fields are covered up by the castings of worms— ^The burial 
of a paved path — ^The slow subsidence of great stones left 
on the surfoce — ^The number of worms which live within a 
given space-*The weight of earth ejected from a burrow, 
and from all the burrows within a given space — ^The thick- 
ness of the layer of mould which the castings on a given 
space would form within a given time if uniformly spread 
out— The slow rate at which mould can increase to a great 
thickness— Conclusion. 

We now come to the more immediate subject 
of this volume, namely, the amount of earth 
which is brought up by worms from beneath 
the surface, and is afterwards spread out more 
or less completely by the rain and wind. The 
amount can be judged of by two methods, — ^by 
the rate at which objects left on the surface are 
buried, and more accurately by weighing the 
quantity brought up within a given time. We 
will begin with the first method, as it was first 
followed. 



122 AMOUNT OF EARTH CHAP. III. 

Near Mael Hall in Staffordshire, quick-lime 
had been spread about the year 1827 thickly 
over a field of good pasture-land, which had 
not since been ploughed. Some square holes 
were dug in this field in the beginning of 
October 1837; ^^^ ^^ sections showed a 
layer of turf, formed by the matted roots of 
the grasses, ^ inch in thickness, beneath which, 
at a depth of 2^ inches (or 3 inches from the 
surface), a layer of the lime in powder or in 
small lumps could be distinctly seen running 
all round the vertical sides of the holes. The 
soil beneath the layer of lime was either 
gravelly or of a coarse sandy nature, and 
differed considerably in appearance from the 
overlying dark-coloured fine mould. Coal- 
cinders had been spread over a part of this 
same field either in the year 1833 or 1834 ; 
and when the above holes were dug, that is 
after an interval of 3 or 4 years, the cinders 
formed a line of black spots round the holes, 
at a depth of i inch beneath the surface, 
parallel to and above the white layer of lime. 
Over another part of this field cinders had 
been strewed, only about half-a-year before, 
and these either still lay on the surface or were 
entangled among the roots of the grasses ; and 



CHAP. III. BROUGHT UP BY WORMS. 1 23 

I here saw the commencement of the burying 
process, for worm-castings had been heaped on 
several of the smaller fragments. After an 
interval of 4! years this field was re-examined, 
and now the two layers of lime and cinders 
were found almost everywhere at a greater 
depth than before by nearly i inch, we will say 
by I of an inch* Therefore mould to an 
average thickness of '22 of an inch had been 
annually brought up by the worms, and had 
been spread over the surface of this field. 

Coal-cinders had been strewed over another 
field, at a date which could not be positively 
ascertained, so thickly that they formed 
(October, 1837) a layer, i inch in thickness at 
a depth of about 3 inches from the surface. 
The layer was so continuous that the over- 
lying dark vegetable mould was connected 
with the sub-soil of red clay only by the roots 
of the grasses ; and when these were broken, 
the mould and the red clay fell apart. In a 
third field, on which coal-cinders and burnt 
marl had been strewed several times at un- 
known dates, holes were dug in 1842; and a 
layer of cinders could be traced at a depth of 
3^ inches, beneath which at a depth of 9^ 
inches from the surface there was a line of 



124 AMOUNT or EARTH CHAP. III. 

cinders together with burnt marl. On the 
sides of one hole there were two layers of 
cinders, at 2 and 3^ inches beneath the sur- 
face ; and below them at a depth in parts of 
g]tf ^nd in other parts of 10^ inches there were 
fragments of burnt marl. In a fourth field two 
layers of lime, one above the other, could be 
distinctly traced, and beneath them a layer of 
cinders and burnt marl at a depth of from 10 
to 12 inches below the surface. 

A piece of waste, swampy land was en- 
closed, drained, ploughed, harrowed and thickly 
covered in the year 1822 with burnt marl and 
cinders. It was sowed with grass seeds, and 
now supports a tolerably good but coarse 
pasture. Holes were dug in this field in 1837, 
or 1 5 years after its reclamation, and we see in 
the accompanying diagram (Fig. 5), reduced to 
half of the natural scale, that the turf was 
^ inch thick, beneath which there was a layer of 
vegetable mould 2^ inches thick. This layer 
did not contain fragments of any kind; but 
beneath it there was a layer of mould, i^ inch 
in thickness, full of fragments of burnt marl, 
conspicuous from their red colour, one of which 
near the bottom was an inch in length ; and 
other fragments of coal-cinders together with a 




Fig. 5. — Section, reduced to half the natural scale, of the vegetable mould 
in a field, drained and reclaimed fifteen years previously ; A. turf ; B, 
vegetable mould without any stones ; C. mould with fragments of burnt 
marl, coal-cinders and quartz pebbles ; D, sub-soil of black, peaty sand 
with quartz pebbles. 




Fig. 6.— Transverse section across a large stone, which had lain on a 
grass-field for 35 years. A A, general level of the field. The underlying 
brick rubbish has not been represented. Scale ^ inch to one foot. 



ITc/act^. 124. 



CHAP. III. BROUGHT UP BY WORMS. 1 25 

few white quartz pebbles. Beneath this layer 
and at a depth of 4^ inches from the surface, 
the original black, peaty, sandy soil with a few 
quartz pebbles was encountered. Here there- 
fore the fragments of burnt marl and cinders 
had been covered in the course of 15 years by 
a layer of fine vegetable mould, only 2^ inches 
in thickness, excluding the turf. Six and a 
half years subsequently this field was re- 
examined, and the fragments were now found 
at from 4 to 5 inches beneath the surface. So 
that in this interval of 6^ years, about i^ inch 
of mould had been added to the superficial 
layer. I am surprised that a greater quantity 
had not been brought up during the whole 21^ 
years, for in the closely underlying black, peaty 
soil there were many worms. It is, however, 
probable that formerly, whilst the land re- 
mained poor, worms were scanty; and the 
mould would then have accumulated slowly. 
The average annual increase of thickness for 
the whole period is *i 9 of an inch. 

Two other cases are worth recording. In 
the spring of 1835, a field, which had long 
existed as poor pasture and was so swampy 
that it trembled slightly when stamped on, was 
thickly covered with red sand so that the whole 



126 AMOUNT OF EARTH CHAP. III. 

surface appeared at first bright red. When 
holes were dug in this field after an interval of 
about 2^ years, the sand formed a layer at a 
depth of I in. beneath the surface. In 1842 
(i.e., 7 years after the sand had been laid on) 
fresh holes were dug, and now the red sand 
formed a distinct layer, 2 inches beneath the 
surface, or i^ inch beneath the turf; so that 
on an average, *2i inch of mould had been 
annually brought to the surface. Immediately 
beneath the layer of red sand, the original 
substratum of black sandy peat extended. 

A grass field, likewise not far from Maer 
Hall, had formerly been thickly covered with 
marl, and was then left for several years as 
pasture ; it was afterwards ploughed. A 
friend had three trenches dug in this field 
28 years after the application of the marl,* 
and a layer of the marl fragments could be 
traced at a depth, carefully measured, of 

* This case is given in a postscript to my paper in the 
* Tnmsact. Geolog. Soc.' (VoL v. p. 505), and contains a serious 
error, as in the account received I mistook the figure 30 for 80. 
The tenant, moreover, formerly said that he had marled the 
field thirty years before, but was now positive that this was 
done in 1809, that is twenty-eight years before the first 
examination of the field by my friend. The error, as far as 
the figure 80 is concerned, was corrected in an article by me, in 
the * Gardeners' Chronicle; 1844, p. 218. 



CHAP. III. BROUGHT UP BY WORMS. 1 27 

12 inches in some parts, and of 14 inches 
in other parts. This difference in depth 
depended on the layer being horizontal, whilst 
the surface consisted of ridges and furrows 
from the field having been ploughed. The 
tenant assured me that it had never been 
turned up to a greater depth than from 6 to 
8 inches; and as the fragments formed an 
unbroken horizontal layer from 12 to 14 inches 
beneath the surface, these must have been 
buried by the worms whilst the land was in 
pasture before it was ploughed, for other- 
wise they would have been indiscriminately 
scattered by the plough throughout the whole 
thickness of the soil. Four-and-a-half years 
afterwards I had three holes dug in this field, 
in which potatoes had been lately planted, and 
the layer of marl-fragments was now found 

13 inches beneath the bottoms of the furrows, 
and therefore probably 15 inches beneath the 
general level of the field. It should, however, 
be observed that the thickness of the blackish 
sandy soil, which had been thrown up by the 
worms above the marl-fragments in the course 
o^ 3^^ years, would have measured less than 
15 inches, if the field had always remained as 
pasture, for the soil would in this case have 



128 AMOUNT OF EARTH CHAP. III. 

been much more compact The fragments of 
marl almost rested on an undisturbed sub- 
stratum of white sand with quartz pebbles; 
and as this would be little attractive to worms, 
the mould would hereafter be very slowly 
increased by their action. 

We will now give some cases of the action 
of worms, on land differing widely from the 
dry sandy or the swampy pastures just 
described. The chalk formation extends all 
round my house in Kent ; and its surface, from 
having been exposed during an immense 
period to the dissolving action of rain-water, 
is extremely irregular, being abruptly festooned 
and penetrated by many deep well-like cavities.* 

* These pits or pipes are still in process of formation. 
During the last forty years I have seen or heard of ^vt cases, 
in which a circular space, several feet in diameter, suddenly fell 
in, leaving on the field an open hole with perpendicular sides, 
some feet in depth. This occurred in one of my own fields, 
whilst it was being rolled, and the hinder quarters of the shaft 
horse fell in ; two or three cart-loads of rubbish were required 
to fill up the hole. The subsidence occurred where there was a 
broad depression, as if the surface had fallen in at several 
former periods. I heard of a hole which must have been 
suddenly formed at the bottom of a small shallow pool, where 
sheep had been washed during many years, and into wliich a 
man thus occupied fell to his great terror. The rain-water over 
this whole district sinks perpendicularly into the ground, but 
the chalk is more porous in certain places than in others. Thus 
the drainage firom the overlying clay is directed to certain 
points, where a greater amount of calcareous matter is dissolved 



CHAP. III. BROUGHT UP BY WORMS. 1 29 

During the dissolution of the chalk, the insoluble 
matter, including a vast number of unrolled 
flints of all sizes, has been left on the surface 
and forms a bed of stiff red clay, full of flints, 
and generally from 6 to 14 feet in thickness. 
Over the red clay, wherever the land has long 
remained as pasture, there is a layer a few 

than elsewhere. Even narrow open channels are sometimes 
formed in the solid chalk. As the chalk is slowly dissolved 
over the whole country, but more in some parts than in others, 
the undissolved residue — ^that is the overlying mass of red clay 
with flints, — ^likewise sinks slowly down, and tends to fill up the 
pipes or cavities. But the upper part of the red clay holds 
together, aided probably by the roots of plants, for a longer 
time than the lower parts, and thus forms a roof, which sooner 
or later falls in, as in the above mentioned five cases. The 
downward movement of the clay may be compared with that of 
a glacier, but is incomparably slower ; and this movement 
accounts for a singular foct, namely, that the much elongated 
flints which are embedded in the chalk in a nearly horizontal 
position, are commonly found standing nearly or quite upright 
in the red clay. This fact is so common diat the workmen 
assured me that this was their natural position. I roughly 
measured one which stood verticaUy, and it was of the 
same length and of the same relative thickness as one 
of my arms. These elongated flints must get placed in 
their upright position, on the same principle that a trunk of 
a tree left on a glacier assumes a position parallel to the 
line of motion. The flints in the clay which form almost 
half its bulk, are very often broken, though not rolled or 
abraded ; and this may be accounted for by their mutual 
pressure, whilst the whole mass is subsiding. I may add that 
the chalk here appears to have been originally covered in parts 
by a thin bed of fine sand with some perfectly rounded flint 
pebbles, probably of Tertiary age ; for such sand often partly 
fills up the deeper pits or cavities in the chalk. 

K 



I30 AMOUNT or EARTH CHAP. 111. 

inches in thickness, of dark-coloured vegetable 
mould. 

A quantity of broken chalk was spread, 
on December 20, 1842, over a part of a field 
near my house, which had existed as pasture 
certainly for 30, probably for twice or thrice 
as many years. The chalk was laid on the 
land for the sakQ of observing at some future 
period to what depth it would become buried. 
At the end of November, 1871, that is after an 
interval of 29 years, a trench was dug across 
this part of the field ; and a line of white nodules 
could be traced on both sides of the trench, at 
a depth of 7 inches from the surface. The 
mould, therefore, (excluding the turf) had here 
been thrown up at an average rate of *22 inch 
per year. Beneath the line of chalk nodules 
there was in parts hardly any fine earth free of 
flints, while in other parts there was a layer, 
2i inches in thickness. In this latter case the 
mould was altogether g{ inches thick ; and in 
one such spot a nodule of chalk and a smooth 
flint pebble, both of which must have been left 
at some former time on the surface, were found 
at this depth. At from 1 1 to 1 2 inches beneath 
the surface, the undisturbed reddish clay, full 
of flints, extended. The appearance of the 



CHAP. III. BROUGHT UP BY WORMS. I3I 

above nodules of chalk surprised me much at 
first, as they closely resembled water-worn 
pebbles^ whereas the freshly-broken fragments 
had been angular. But on examining the 
nodules with a lens, they no longer appeared 
water-worn, for their surfaces were pitted 
through unequal corrosion, and minute, sharp 
points, formed of broken fossil shells, projected 
from them. It was evident that the comers of 
the original fragments of chalk had been wholly 
dissolved, from presenting a large surface to 
the carbonic acid dissolved in the rain-water 
and to that generated in soil containing vege- 
table matter, as well as to the humus-acids.* 
The projecting corners would also, relatively 
to the other parts, have been embraced by 
a larger number of living rootlets ; and these 
have the power of even attacking marble, as 
Sachs has shown. Thus, in the course of 29 
years, buried angular fragments of chalk had 
been converted into well-rounded nodules. 

Another part of this same field was mossy, 
and as it was thought that sifted coal-cinders 
would improve the pasture, a thick layer was 
spread over this part either in 1842 or 1843, 
and another layer some years afterwards. In 
* S. W. Johnson, ' How Crops Feed,' 1870^ p. 139. 



132 AMOUNT OF EARTH CHAF. III. 

1871 a trench was here dug, and many cinders 
lay in a line at a depth of 7 inches beneath the 
surface, with another line at a depth of 5^ inches 
parallel to the one beneath. In another part 
of this field, which had formerly existed as a 
separate one, and which it was believed had 
been pasture-land for more than a century, 
trenches were dug to see how thick the v^e- 
table mould was. By chance the first trench 
was made at a spot where at some former 
period, certainly more than forty years before, 
a large hole had been filled up with coarse red 
clay, flints, fragments of chalk, and gravel; 
and here the fine vegetable mould was only 
from 4I to 4I inches in thickness. In another 
and undisturbed place, the mould varied much 
in thickness, namely, from 6t^ to 8j^ inches; 
beneath which a few small fragments of brick 
were found in one place. From these several 
cases, it would appear that during the last 29 
years mould has been heaped on the surface 
at an average annual rate of from '2 to '22 of 
an inch. But in this district when a ploughed 
field is first laid down in grass, the mould 
accumulates at a much slower rate. The rate, 
also, must become very much slower after a bed 
of mould, several inches in thickness, has been 



CHAP. III. BROUGHT UP BY WORMS. 1 33 

fonned ; for the worms then live chiefly near 
the surface, and burrow down to a greater 
depth so as to bring up fresh earth from below, 
only during the winter when the weather is 
very cold (at which time worms were found in 
this field at a depth of 26 inches) and during 
summer, when the weather is very dry. 

A field, which adjoins the one just described, 
slopes in one part rather steeply (viz., at from 
10^ to 15^); this part was last ploughed in 
1 84 1, was then harrowed and left to become 
pasture-land. For several years it was clothed 
with an extremely scant vegetation, and was 
so thickly covered with small and large flints 
(some of them half as large as a child's head) 
that the field was always called by my sons 
"the stony field." When they ran down the 
slope the stones clattered together. I remember 
doubting whether I should live to see these 
larger flints covered with vegetable mould and 
turf. But the smaller stones disappeared before 
many years had elapsed, as did every one of 
the larger ones after a time ; so that after thirty 
years (1871) a horse could gallop over the 
compact turf from one end of the field to the 
other, and not strike a single stone with his 
shoes. To anyone who remembered the 



134 AMOUNT OF EARTH CHAP. ill. 

appearance of the field in 18421 the transforma- 
tion was wonderful. This was certainly the 
work of the worms, for though castings were 
not frequent for several years, yet some were 
thrown up month after month, and these 
gradually increased in numbers as the pasture 
improved. In the year 1871 a trench was dug 
on the above slope, and the blades of grass 
were cut off close to the roots, so that the 
thickness of the turf and of the vegetable mould 
could be measured accurately. The turf was 
rather less than half an inch, and the mould, 
which did not contain any stones, 2^ inches in 
thickness. Beneath this lay coarae clayey 
earth full of flints, like that in any of the 
neighbouring ploughed fields. This coarse 
earth easily fell apart from the overlying mould 
when a spit was lifted up. The average rate 
of accumulation of the mould during the whole 
thirty years was only '083 inch per year (i,e., 
nearly one inch in twelve yeara) ; but the rate 
must have been much slower at first, and after- 
wards considerably quicker. 

The transformation in the appearance of 
this field, which had been effected beneath my 
eyes, was afterwards rendered the more striking, 
when I examined in Knole Park a dense forest 



CHAP. III. BROUGHT UP BY WORMS. 135 

of lofty beech*trees» beneath which nothing 
grew. Here the ground was thickly strewed 
with large naked stones, and worm-castings 
were almost wholly absent Obscure lines and 
irregularities on the surface indicated that the 
land had been cultivated some centuries ago. 
It is probable that a thick wood of young beech- 
trees sprung up so quickly, that time enough 
was not allowed for worms to cover up the 
stones with their castings, before the site 
became unfitted for their existence. Anyhow 
the contrast between the state of the now mis- 
called *• stony fietd/' well stocked with worms, 
and the present state of the ground beneath 
the old beech-trees in Knole Park, where 
worms appeared to be absent, was striking. 

A narrow path running across part of my 
lawn was paved in 1843 with small flagstones, 
set edgeways ; but worms threw up many cast- 
ings and weeds grew thickly between them. 
During several years the path was weeded and 
swept; but ultimately the weeds and worms 
prevailed, and the gardener ceased to sweep, 
merely mowing off the weeds, as often as the 
lawn was mowed. The path soon became 
almost covered up, and after several years no 
trace of it was left. On removing, in 1877, the 



136 AMOUNT OF EARTH CHAP. III. 

thin overlying layer of turf, the small flag-stones, 
all in their proper places, were found covered 
by an inch of fine mould. 

Two recently published accounts of sub- 
stances strewed on the surface of pasture*land, 
having become buried through the action of 
worms, may be here noticed. The Rev, H. C. 
Key had a ditch cut in a field, over which coal- 
ashes had been spread, as it was believed, 
eighteen years before; and on the clean-cut 
perpendicular sides of the ditch, at a depth of 
at least seven inches, there could be seen, for a 
length of 60 yards, " a distinct, very even, 
** narrow line of coal-ashes, mixed with small 
" coal, perfectly parallel with the top-sward/'* 
This parallelism and the length of the section 
give interest to the case. Secondly, Mr. 
Dancer states f that crushed bones had been 
thickly strewed over a field ; and " some years 
" afterwards " these were found " several inches 
" below the surface, at a uniform depth." 

The Rev. Mr. Zincke informs me that he 
has lately had an orchard dug to the unusual 
depth of 4 feet. The upper 18 inches consisted 
of dark-coloured vegetable mould, and the next 

• * Nature,* November 1877, p. 28. 

t ' Proc. Phil. Soc.* of Manchester, 1877, p. 247. 



CHAP. III. BROUGHT UP BY WORMS. 1 37 

1 8 inches of sandy loanii containing in the lower 
part many rolled pieces of sandstone, with some 
bits of brick and tile, probably of Roman origin, 
as remains of this period have been found close 
by. The sandy loam rested on an indurated 
ferruginous pan of yellow clay, on the surface of 
which two perfect celts were found. If, as 
seems probable, the celts were originally left on 
the surface of the land, they have since been 
covered up with earth 3 feet in thickness, all of 
which has probably passed through the bodies 
of worms, excepting the stones which may have 
been scattered on the surface at different times, 
together with manure or by other means. It is 
difficult otherwise to understand the source of 
the 18 inches of sandy loam, which differed from 
the overlying dark v^etable mould, after both 
had been burnt, only in being of a brighter 
red colour, and in not being quite so fine- 
grained. But on this view we must suppose 
that the carbon in vegetable mould, when it 
lies at some little depth beneath the surface 
and does not continually receive decaying 
vegetable matter from above, loses its dark 
colour in the course of centuries ; but whether 
this is probable I do not know. 

Worms appear to act in the same manner 



138 GREAT STONES CHAP. III. 

in New Zealand as in Europe ; for Professor J. 
von Haast has described * a section near the 
coast, consisting of mica-schist, " covered by 5 
'' or 6 feet of loess, above which about 1 2 inches 
'' of vegetable soil had accumulated." Between 
the loess and the mould there was a layer from 
3 to 6 inches in thickness, consisting of '' cores, 
*^ implements, flakes, and chips, all manufactured 
''from hard basaltic rock." It is therefore 
probable that the aborigines, at some former 
period, had left these objects on the surface, 
and that they had afterwards been slowly 
covered up by the castings of worms. 

Farmers in England are well aware that 
objects of all kinds, left on the surface of 
pasture-land, after a time disappear, or, as 
they say, work themselves downwards. How 
powdered lime, cinders, and heavy stones, can 
work down, and at the same rate, through the 
matted roots of a grass-covered surface, is a 
question which has probably never occurred to 
them.f 

* * Trans, of the New Zealand Institute/ voL zii., 1880, p. 152. 

t Mr. Lindsay Camagie, in a letter (June 1838) to Sir C. 
Lydl, remarks that Scotch fanners are afraid of putting lime on 
ploughed land until just before it is laid down for pasture, from 
a belief that it has some tendency to sink. He adds : '* Some 
years since, in autumn, I laid lime on an oat-stubble and ploughed 
it down ; thus bringing it into immediate contact with the dead 



CHAP. III. UNDERMINED BY WORMS. 1 39 

The Sinking of great Stams through the 
Action of Worms. — ^When a stone of large size 
and of irregular shape is left on the surface 
of the ground, it rests, of course, on the more 
protuberant parts ; but worms soon fill up with 
their castings all the hollow spaces on the lower 
side; for, as Hensen remarks, they like the 
shelter of stones. As soon as the hollows are 
filled up, the worms eject the earth which they 
have swallowed beyond the circumference of 
the stones ; and thus the surface of the ground 
b raised all round the stone. As the burrows 
excavated directly beneath the stone after a 
time collapse, the stone sinks a little.* Hence 
it is, that boulders which at some ancient period 
have rolled down from a rocky mountain or cliff 
on to a meadow at its base, are always some- 
what imbedded in the soil ; and, when removed. 



vegetable matter, and securing its thorough mixture through the 
means of all the subsequent operations of fallow. In conse- 
quence of the above prejudice, I was considered to have committed 
a great fault ; but the result was eminently successful, and the 
practice was partialfy followed. By means of Mr. Darwin's 
observations, I think the prejudice indll be removed.* 

* This condusion/which, as we shall immediately see, is fully 
justified, is of some little importance, as the so-called bench- 
stones, which surveyors fix in the ground as a record of their 
levels, may in time become false standards. My son Horace 
intends at some future period to ascertain how far this has 
occuiredt 



I40 GREAT STONES CHAP, III. 

leave an exact impression of their lower surfaces 
in the underlying fine mould. If, however, a 
boulder is of such huge dimensions, that the 
earth beneath is kept dry, such earth will not 
be inhabited by worms, and the boulder will 
not sink into the ground. 

A lime-kiln formerly stood in a grass-field 
near Leith Hill Place in Surrey, and was 
pulled down 35 years before my visit ; all the 
loose rubbish had been carted away, excepting 
three large stones of quartzose sandstone, 
which it was thought might hereafter be of 
some use. An old workman remembered that 
they had been left on a bare surface of broken 
bricks and mortar, close to the foundations of 
the kiln ; but the whole surrounding surface is 
now covered with turf and mould. The two 
largest of these stones had never since been 
moved ; nor could this easily have been done, 
as, when I had them removed, it was the work 
of two men with levers. One of these stones, 
and not the largest, was 64 inches long, 17 
inches broad, and from 9 to 10 inches in thick- 
ness. Its lower surface was somewhat pro- 
tuberant in the middle; and this part still 
rested on broken bricks and mortar, show- 
ing the truth of the old workman's account 



CHAP. UK UNDERMINED BY WORMS. I4I 

Beneath the brick rubbish the natural sandy soil, 
full of fragments of sandstone was found ; and 
this could have yielded very littlei if at all, to 
the weight of the stone, as might have been 
expected if the sub-soil had been clay. The 
surface of the field, for a distance of about 
9 inches round the stone, gradually sloped up 
to it, and close to the stone stood in most 
places about 4 inches above the surrounding 
ground. The base of the stone was buried 
from I to 2 inches beneath the general level, 
and the upper surface projected about 8 inches 
above this level, or about 4 inches above the 
sloping border of turf. After the removal of 
the stone it became evident that one of its 
pointed ends must at first have stood clear 
above the ground by some inches, but its 
upper surface was now on a level with the 
surrounding turf. When the stone was re- 
moved, an exact cast of its lower side, forming 
a shallow crateriform hollow, was left, the 
inner surface of which consisted of fine black 
mould, excepting where the more protuberant 
parts rested on the brick-rubbish. A trans- 
verse section of this stone, together with its 
bed, drawn from measurements made after it 
had been displaced, is here given on a scale of 



142 GREAT STONES CHAP. III. 

^ inch to a foot (Fig. 6). The turf-covered 
border which sloped up to the stone, consisted 
of fine vegetable mould, in one part 7 inches in 
thickness. Thb evidently consisted of worm- 
castings, several of which had been recently 
ejected. The whole stone had sunk in the 
thirty-five years, as far as I could judge, about 
i^ inch; and this must have been due to the 
brick-rubbish beneath the more protuberant 
parts having been undermined by worms. At 
this rate the upper surface of the stone, if it 
had been left undisturbed, would have sunk to 
the general level of the field in 247 years ; but 
before this could have occurred, some earth 
would have been washed down by heavy rain 
from the castings on the raised border of turf 
over the upper surface of the stone. 

The second stone was larger that the one 
just described, viz., 67 inches in length, 39 in 
breadth, and 15 in thickness. The lower 
surface was nearly flat, so that the worms must 
soon have been compelled to eject their cast- 
ings beyond its circumference. The stone as a 
whole had sunk about 2 inches into the ground. 
At this late it would have required 262 years 
for its upper surface to have sunk to the 
general level of the field. The upwardly 



CHAP. III. UNDERMINED BY WORMS. 1 43 

sloping, turf-covered border round the stone 
was broader than in the last case, viz., from 14 
to 16 inches; and why this should be so, I 
could see no reason. In most parts this 
border was not so high as in the last case, viz., 
from 3 to 2^ inches, but in one place it was as 
much as 5^. Its average height close to the 
stone was probably about 3 inches, and it 
thinned out to nothing. If so, a layer of fine 
earth, 15 inches in breadth and i^ inch in 
average thickness, of sufficient length to sur« 
round the whole of the much elongated slab, 
must have been brought up by the worms in 
chief part from beneath the stone in the course 
of 35 years. This amount would be amply 
sufficient to account for its having sunk about 
2 inches into the ground; more especially if 
we bear in mind that a good deal of the finest 
earth would have been washed by heavy rain 
from the castings ejected on the sloping border 
down to the level of the field. Some fresh 
castings were seen close to the stone. Never- 
theless, on digging a large hole to a depth of 
18 inches where the stone had lain, only two 
worms and a few burrows were seen, although 
the soil was damp and seemed favourable for 
worms. There were some large colonies of 



144 GREAT STONES CHAP. III. 

ants beneath the stone, and possibly since their 
establishment the worms had decreased in 
number. 

The third stone was only about half as 
large as the others ; and two strong boys could 
together have rolled it over. I have no doubt 
that it had been rolled over at a moderately 
recent time, for it now lay at some distance 
from the two other stones at the bottom of a 
little adjoining slope. It rested also on fine 
earth, instead of partly on brick-rubbish« In 
agreement with this conclusion, the raised sur- 
rounding border of turf was only i inch high 
in some parts, and 2 inches in other parts. 
There were no colonies of ants beneath this 
stone, and on digging a hole where it had lain, 
several burrows and worms were found. 

At Stonehenge, some of the outer Druidical 
stones are now prostrate, having fallen at a 
remote but unknown period; and these have 
become buried to a moderate depth in the 
ground. They are surrounded by sloping 
borders of turf, on which recent castings were 
seen. Close to one of these fallen stones, 
which was 17 ft long, 6 ft broad, and 28^ 
inches thick, a hole was dug; and here the 
vegetable mould was at least gi inches in 



CHAP. III. UNDERMINED BY WORMS. 1 45 

thickness. At this depth a flint was found, 
and a little higher up on one side of the hole 
a fragment of glass. The base of the stone 
lay about gj^ inches beneath the level of the 
surrounding ground, and its upper surface 
19 inches above the ground 

A hole was also dug close to a second huge 
stone, which in falling had broken into two 
pieces; and this must have happened long 
agOf judging from the weathered aspect of 
the fractured ends. The base was buried to 
a depth of lo inches, as was ascertained by 
driving an iron skewer horizontally into the 
ground beneath it. The vegetable mould 
forming the turf-covered sloping border round 
the stone, on which many castings had re- 
cently been ejected, was lo inches in thickness; 
and most of this mould must have been 
brought up by worms from beneath its base. 
At a distance of 8 yards from the stone, the 
mould was only 5^ inches in thickness (with 
a piece of tobacco pipe at a depth of 4 inches), 
and this rested on broken flint and chalk which 
could not have easily yielded to the pressure 
or weight of the stone. 

A straight rod was fixed horizontally (by 
the aid of a spirit-level) across a third fallen 

L 



146 GREAT STONES CHAP. III. 

Stone, which was 7 feet 9 inches long ; and the 
contour of the projecting parts and of the 
adjoining ground, which was not quite level, 
was thus ascertained, as shown in the ac- 
companying diagram (Fig. 7) on a scale of 
^ inch to a foot. The turf-covered border 
sloped up to the stone on one side to a height 
of 4 inches, and on the opposite side to only 
2^ inches above the general level. A hole 
was dug on the eastern side, and the base of 
the stone was here found to lie at a depth of 
4 inches beneath the general level of the 
ground, and of 8 inches beneath the top of the 
sloping turf-covered border. 

Sufficient evidence has now been given 
showing that small objects left on the surface 
of the land where worms abound soon get 
buried, and that large stones sink slowly 
downwards through the same means. Every 
step of the process could be followed, from the 
accidental deposition of a single casting on a 
small object lying loose on the surface, to its 
being entangled amidst the matted roots of 
the turf, and lastly to its being embedded in 
the mould at various depths beneath the 
surface. When the same field was re-examined 



CHAP. III. UNDERMINED BY WORMS, 1 47 

after the interval of a few years, such objects 
were found at a greater depth than before. 
The straightness and regularity of the lines 
formed by the imbedded objects, and their 
parallelism with the surface of the land, are 
the most striking features of the case ; for this 
parallelism shows how equably the worms must 
have worked ; the result being, however, partly 
the effect of the washing down of the fresh 
castings by rain. The specific gravity of the 
objects does not affect their rate of sinking, as 
could be seen by porous cinders, burnt marl, 
chalk and quartz pebbles, having all sunk to 
the same depth within the same time. Con- 
sidering the nature of the substratum, which at 
Leith Hill Place was sandy soil including many 
bits of nrock, and at Stonehenge, chalk-rubble 
with broken flints ; considering, also, the 
presence of the turf-covered sloping border of 
mould round the great fragments of stone at 
both these places, their sinking does not appear 
to have been sensibly aided by their weight, 
though this was considerable.* 

* Mr. R. Mallet remarks (' Quarterly Journal of Geolog. 
Soc' vol. xxxiii., 1877, p. 745)tliaf the extent to which the 
ground beneath the foundations of ponderous architectural 
structures, such as cathedral towers, has been known to become 
compressed, is as remarkable as it is instructive and curious. 



148 NUMBER OF WORMS. CHAP. III. 

On the number of worms which live within 
a given space. — We will now show, firstly, what 
a vast number of worms live unseen by us 
beneath our feet, and, secondly, the actual 
weight of the earth which they bring up to 
the surface within a given space and within 
a given time« Hensen, who has published so 
full and interesting an account of the habits 
of worms,* calculates, from the number which 
he found in a measured space, that there must 
exist 133,000 living worms in a hectare of 
land, or 53,767 in an acre. This latter number 
of worms would weigh 356 pounds, taking 
Hensen's standard of the weight of a single 
worm, namely, three grams. It should, how- 
ever, be noted that this calculation is founded 
on the numbers found in a garden, and Hensen 
believes that worms are here twice as numerous 
as in corn-fields. The above result, astonishing 
though it be, seems to me credible, judging 
from the number of worms which I have some- 
times seen, and from the number daily destroyed 
by birds without the species being exterminated. 
Some barrels of bad ale were left on Mr. 

The amount of depression in some cases may be measured by 
feet" He instances the Tower of Pisa, but adds that it was 
founded on ^ dense clay." 

* ' Zeitschrift fUr wissensch. Zoolog.' Bd. xxviii., 1877, p. 36a 



CHAP. III. NUMBER OF WORMS. I49 

Miller's land,* in the hope of making vinegar, 
but the vinegar proved bad, and the barrels 
were upset. It should be premised that acetic 
acid is so deadly a poison to worms that 
Perrier found that a glass rod dipped into 
this acid and then into a considerable body of 
water in which worms were immersed, in- 
variably killed them quickly. On the morning 
after the barrels had been upset, ''the heaps 
" of worms which lay dead on the ground were 
"so amazing, that if Mr. Miller had not seen 
" them, he could not have thought it possible 
"for such numbers to have existed in the 
"space." As further evidence of the large 
number of worms which live in the ground, 
Hensen states that he found in a garden sixty- 
four open burrows in a space of 14^ square feet, 
that is, nine in 2 square feet. But the burrows 
are sometimes much more numerous, for when 
digging in a grass-field near Maer Hall, I found 
a cake of dry earth, as large as my two open 
hands, which was penetrated by seven burrows, 
as large as goose-quills. 

Weight of the earth ejected from a single 
burrow^ and from all the burrows within a given 

* See Mr. Dancer's paper in < Proc. Phil. Soc of Manchester,' 
i877f p. 248. 



150 WEIGHT OF EARTH CHAP. HI. 

Space. — With respect to the weight of the earth 
daily ejected by worms, Hensen found that it 
amounted, in the case of some worms which he 
kept in confinement, and which he appears to 
have fed with leaves, to only o'5 gram, or less 
than 8 grains per diem. But a very much 
larger amount must be ejected by worms in 
their natural state, at the periods when they 
consume earth as food instead of leaves, and 
when they are making deep burrows. This 
is rendered almost certain by the following 
weights of the castings thrown up at the 
mouths of single burrows ; the whole of which 
appeared to have been ejected within no long 
time, as was certainly the case in several 
instances. The castings were dried (except- 
ing in one specified instance) by exposure 
during many days to the sun or before a 
hot fire. 

Weight of the Castings accumulated at the mouth 
OF A SINGLE Burrow. 



(1.) Down, Kent (sub-soil red day, full of flints, over-' 
lying the chalk). The largest casting which 
I could find on the flanks of a stee^ valley, the 
sub-soil being here shallow. In this one case, 
the casting was not well dried 

(2.) Down. — Laiq^t casting which I could find 
(consisting chiefly of calcareous matter), on 
extremely poor pasture land at the bottom of 
the valley mentioned under ( i .) 



Oonott. 
3-98 



fl 



CHAP. 111. BROUGHT UP BY WORMS. 151 

Ounces 

(3.) Down.-^A large casting^ bat not of unusual size.) 

from a nearly level field, poor pasture, laia[ 1*22 
down in grass about 35 years before .. .. I 

(4.) Down.— Average weight of 1 1 not laige castings 
eiected on a sloping surface on my lawn, after 
they had suffered some loss of weight from * 07 
being exposed during a considerable length of 
time to rain 

(5.) Near Nice in France. — ^Average weight of 12^ 
castings of ordinary dimensions, collected by 
Dr. Kmg on land which had not been mown 
for a long time and where worms abounded, 
viz., a lawn protected by shrubberies, near the] 1*37 
sea ; soil sandy and calcareous ; these castings 
had been exposed for some time to rain, before 
being collected, and must have lost some 
weight by disintegration, but they still re- 

tained their form / 

The heaviest of the above twelve castings 176 

Lower Bengal.— Average weight of 22 castings, ^ 
collected by Mr. J. Scott, and stated by hmil 
to have been thrown up in the course of one | ^ 
or two nights j 

(8.^ The heaviest of the above 22 castings .. 2*09 

(9.) Nilgiri Mountains, S. India ; average weight of) 
the 5 largest castings collected by Dr. King. I 
They had been exposed to the rain of the lastf ^ ^ 
monsoon, and must have lost some weight ../ 

(10.) The heaviest of the above 5 castings . . 4*34 

In this table we see that castings which had 
been ejected at the mouth of the same burrow, 
and which in most cases appeared fresh and 
always retained their vermiform configuration, 
generally exceeded an ounce in weight after 
being dried, and sometimes nearly equalled a 
quarter of a pound. On the Nilgiri mountains 
one casting even exceeded this latter weight 
The largest castings in England were found 



152 WEIGHT OF EARTH CHAP. III. 

on extremely poor pasture-land ; and these, as 
far as I have seen, are generally larger than 
those on land producing a rich vegetation. It 
would appear that worms have to swallow a 
greater amount of earth on poor than on rich 
land, in order to obtain sufficient nutriment 

With respect to the tower-like castings 
near Nice (Nos. 5 and 6 in the above table), 
Dr. King often found five or six of them on 
a square foot of surface; and these, judging 
from their average weight, would have weighed 
together 7^ ounces ; so that the weight of those 
on a square yard would have been 4 lb. 3^ oz. 
Dr. King collected, near the close of the year 
1872, all the castings which still retained their 
vermiform shape, whether broken down or not, 
from a square foot, in a place abounding with 
worms, on the summit of a bank, where no 
castings could have rolled down from above. 
These castings must have been ejected, as he 
judged from their appearance in reference to 
the rainy and dry periods near Nice, within 
the previous five or six months ; they weighed 
9^ oz., or 5 lb. 5^ oz. per square yard. After 
an interval of four months, Dr. King collected 
all the castings subsequently ejected on the 
same square foot of surface, and they weighed 



CHAP. III. BROUGHT UP BY WORMS. 1 53 

2^ oz., or I lb. 6 J oz. per square yard There- 
fore within about ten months, or we will say 
for safet/s sake within a year, 1 2 oz. of castings 
were thrown up on this one square foot, or 675 
pounds on the square yard; and this would 
give 14*58 tons per acre. 

In a field at the bottom of a valley in the 
chalk (see No. 2 in the foregoing table), a 
square yard was measured at a spot where 
very large castings abounded ; they appeared, 
however, almost equally numerous in a few 
other places. These castings, which retained 
perfectly their vermiform shape, were col- 
lected; and they weighed when partially 
dried, i lb. 13^ oz. This field had been 
rolled with a heavy agricultural roller fifty-two 
days before, and this would certainly have 
flattened every single casting on the land. 
The weather had been very dry for two or 
three weeks before the day of collection, so 
that not one casting appeared fresh or had 
been recently ejected. We may therefore 
assume that those which were weighed had 
been ejected within, we will say, forty days 
from the time when the field was rolled, — 
that is, twelve days short of the whole inter- 
vening period. I had examined the same 



154 WEIGHT OF EARTH CHAP. III. 

part of the field shortly before it was rolled, 
and it then abounded with fresh castings. 
Worms do not work in dry weather during 
the summer, or in winter during severe frosts. 
If we assume that they work for only half the 
year — ^though this is too low an estimate — then 
the worms in this field would eject during the 
year, 8*387 pounds per square yard ; or 18*12 
tons per acre, assuming the whole surface to 
be equally productive in castings. 

In the foregoing cases some of the neces- 
sary data had to be estimated, but in the two 
following cases the results are much more 
trustworthy. A lady, on whose accuracy I 
can implicitly rely, offered to collect during a 
year all the castings thrown up on two separate 
square yards, near Leith Hill Place, in Surrey. 
The amount collected was, however, somewhat 
less than that originally ejected by the worms ; 
for, as I have repeatedly observed, a good deal 
of the finest earth is washed away, whenever 
castings are thrown up during or shortly before 
heavy rain. Small portions also adhered to 
the surrounding blades of grass, and it required 
too much time to detach every one of them. 
On sandy soil, as in the present instance, cast- 
ings are liable to crumble after dry weather. 



CHAP. III. BROUGHT UP BY WORMS. 1 55 

and particles were thus often lost The lady 
also occasionally left home for a week or two, 
and at such times the castings must have 
suffered still greater loss from exposure to the 
weather. These losses were, however, com- 
pensated to some extent by the collections 
having been made on one of the squares for 
four days, and on the other square for two 
days more than the year. 

A space was selected (October 9th, 1870) 
for one of the squares on a broad, grass- 
covered terrace, which had been mowed and 
swept during many years. It faced the south, 
but was shaded during part of the day by 
trees. It had been formed at least a century 
ago by a great accumulation of small and 
large fragments of sandstone, together with 
some sandy earth, rammed down level It is 
probable that it was at first protected by being 
covered with turf. This terrace, judging from 
the number of castings on it, was rather un- 
favourable for the existence of worms, in com- 
parison with the neighbouring fields and an 
upper terrace. It was indeed surprising that 
as many worms could live here as were seen ; 
for on digging a hole in this terrace, the black 
vegetable mould together with the turf was 



156 WEIGHT OF EARTH CHAP. III. 

only four inches in thickness, beneath which 
lay the level surface of light-coloured sandy 
soil, with many fragments of sandstone. Before 
any castings were collected all the previously 
existing ones were carefully removed. The 
last da/s collection was on October 14th, 1871. 
The castings were then well dried before a 
fire; and they weighed exactly 3 J lbs. This 
would give for an acre of similar land 7*56 tons 
of dry earth annually ejected by worms. 

The second square was marked on un- 
enclosed common land, at a height of about 
700 ft. above the sea, at some little distance 
from Leith Hill Tower. The surface was 
clothed with short, fine turf, and had never 
been disturbed by the hand of man. The 
spot selected appeared neither particularly 
favourable nor the reverse for worms ; but I 
have often noticed that castings are especially 
abundant on common land, and this may, 
perhaps, be attributed to the poorness of 
the soil. The vegetable mould was here 
between three and four inches in thickness. 
As this spot was at some distance from the 
house where the lady lived, the castings were 
not collected at such short intervals of time 
as those on the terrace; consequently the 



CHAP. III. BROUGHT UP BY WORMS. 157 

loss of fine earth during rainy weather must 
have been greater in this than in the last 
case. The castings moreover were more 
sandy, and in collecting them during dry 
weather they sometimes crumbled into dust, 
and much was thus lost. Therefore it is 
certain that the worms brought up to the 
surface considerably more earth than that 
which was collected. The last collection was 
made on October 27th, 1871 ; Le., 367 days 
after the square had been marked out and the 
surface cleared of all pre-existing castings. 
The collected castings, after being well dried, 
weighed 7*453 pounds; and this would give, 
for an acre of the same kind of land, i6'i tons 
of annually ejected dry earth. 

Summary of the four foregoing Cases. 

(i.) Castings ejected near Nice within about a year, collected 
by Dr. King on a square foot of surface, calculated to yield per 
acre 14*58 tons. 

(2.) Castings ejected during about 40 days on a square 
yard, in a field of poor pasture at the bottom of a large valley 
in the Chalk, calculated to yield annually per acre 18' 12 tons. 

(3.) Castings collected from a square yard on an old terrace 
at Leith Hill Place, during 369 days, calculated to yield annually 
per acre 7*56 tons. 

(4.) Castings collected from a square yard on Leith Hill 
Common during 367 days, calculated to yield annually per acre 
16*1 tons. 

The thickness of the layer of mouldy which 



158 THICKNESS OF THE MOULD CHAP. III. 

castings ejected during a year would farm if 
uniformly spread out. — ^As we know, from the 
two last cases in the above summary, the 
weight of the dried castings ejected by worms 
during a year on a square yard of surface, I 
wished to learn how thick a layer of ordinary 
mould this amount would form if spread uni- 
formly over a square yard. The dry castings 
were therefore broken into small particles, and 
whilst being placed in a measure were well 
shaken and pressed down. Those collected on 
the Terrace amounted to 12477 cubic inches ; 
and this amount, if spread out over a square 
yard, would make a layer 0*9627 inch in 
thickness. Those collected on the Common 
amounted to 197*56 cubic inches, and would 
make a similar layer '1524 inch in thickness. 

These thicknesses must, however, be cor- 
rected, for the triturated castings, after being 
well shaken down and pressed, did not make 
nearly so compact a mass as vegetable mould, 
though each separate particle was very com- 
pact Yet mould is far from being compact, 
as is shown by the number of air-bubbles 
which rise up when the surface is flooded with 
water. It is moreover penetrated by many 
fine roots. To ascertain approximately by 



CHAP. III. ANNUALLY ACCUMULATED. 1 59 

how much ordinary vegetable mould would be 
increased in bulk by being broken up into 
small particles and then dried, a thin oblong 
block of somewhat argillaceous mould (with 
the turf pared off) was measured before being 
broken up, was well dried and again measured. 
The drying caused it to shrink by f of its 
original bulk, judging from exterior measure- 
ments alone. It was then triturated and partly 
reduced to powder, in the same manner as the 
castings had been treated, and its bulk now 
exceeded (notwithstanding shrinkage from dry- 
ing) by ^ that of the original block of damp 
mould. Therefore the above calculated thick- 
ness of the layer, formed by the castings from 
the Terrace, after being damped and spread 
over a square yard, would have to be reduced 
by T^ff ; and this will reduce the layer to "09 of 
an inch, so that a layer *9 inch in thickness 
would be formed in the course of ten years. 
On the same principle the castings from the 
Common would make in the course of a single 
year a layer U429 inch, or in the course of 10 
years 1*429 inch, in thickness. We may say 
in roimd numbers that the thickness in the 
former case would amount to nearly i inch, and 
in the second case to nearly i| inch in 10 years. 



l60 THICKNESS OF THE MOULD CHAP. III. 

In order to compare these results with 
those deduced from the rates at which small 
objects left on the surfaces of grass-fields 
become buried (as described in the early part 
of this chapter), we will give the following 
summary : — 

Summary of the thickness of the Mould accumulated 
OVER Objects left strewed on the Surface, in 
the covkse of ten years. 

The accumulation of mould during 14} years on the surface 
of a dry, sandy, grass-field near Maer Hall, amounted to 2*2 
inches in 10 years. 

The accumulation during 21^ years on a swampy field near 
Maer Hall, amounted to nearly 1*9 inch in 10 years. 

The accumulation during 7 years on a very swampy field 
near Maer Hall amounted to 2*1 inches in 10 years. 

The accumulation during 29 years, on good, argillaceous 
pasture-land over the Chalk at Down, amounted to 2*2 inches 
in 10 years. 

The accumulation during 30 years on the side of a valley 
over the Chalk at Down, the soil being argillaceous, very poor, 
and only just converted into pasture (so that it was for some 
years unfavourable for worms), amounted to 0*83 inch in 10 
years. 

In these cases (excepting the last) it may be 
seen that the amount of earth brought to the 
surface during 10 years is somewhat greater 
than that calculated from the castings which 
were actually weighed This excess may be 
partly accounted for by the loss which the 
weighed castings had previously undergone 



CHAP. in. ANNUALLY ACCUMULATED. l6l 

through being washed by rain, by the adhesion 
of particles to the blades of the surrounding 
grass, and by their crumbling when dry. Nor 
must we overlook other agencies which in all 
ordinary cases add to the amount of mould, 
and which would not be included in the castings 
that were collected, namely, the fine earth 
brought up to the surface by burrowing larvae 
and insects, especially by ants. The earth 
brought up by moles generally has a somewhat 
different appearance from vegetable mould; 
but after a time would not be distinguishable 
from it In dry countries, moreover, the wind 
plays an important part in carrying dust from 
one place to another, and even in England it 
must add to the mould on fields near great 
roads. But in our country these latter several 
agencies appear to be of quite subordinate 
importance in comparison with the action of 
worms. 

We have no means of judging how great a 
weight of earth a single full-sized worm ejects 
during a year. Hensen estimates that 53,767 
worms exist in an acre of land; but this is 
founded on the number found in gardens, and 
he believes that only about half as many live 
in corn-fields. How many live in old pasture 

M 



1 62 THICKNESS OF THE MOULD CHAP. III. 

land is unknown ; but if we assume that half 
the above number, or 26,886 worms live on 
such land, then taking from the previous sum- 
mary 15 tons as the weight of the castings 
annually thrown up on an acre of land, each 
worm must annually eject 20 ounces. A full- 
sized casting at the mouth of a single burrow 
often exceeds, as we have seen, an ounce in 
weight; and it is probable that worms eject 
more than 20 full-sized castings during a year. 
If they eject annually more than 20 ounces, 
we may infer that the worms which live in an 
acre of pasture land must be less than 26,886 in 
number. 

Worms live chiefly in the superficial mould, 
which is usually from 4 or 5 to 10 and even 
12 inches in thickness; and it is this mould 
which passes over and over again through 
their bodies and is brought to the surface. 
But worms occasionally burrow into the sub- 
soil to a much greater depth, and on such 
occasions they bring up earth from this greater 
depth ; and this process has gone on for count- 
less ages. Therefore the superficial layer of 
mould would ultimately attain, though at a 
slower and slower rate, a thickness equal to 
the depth to which worms ever burrow, were 



CHAP. III. ANNUALLY ACCUMULATED. 163 

there not other opposing agencies at work 
which carry away to a lower level some of the 
finest earth which is continually being brought 
to the surface by worms. How great a thick- 
ness vegetable mould ever attains, I have not 
had good opportunities for observing; but in 
the next chapter, when we consider the burial 
of ancient buildings, some facts will be given 
on this head. In the two last chapters we 
shall see that the soil is actually increased, 
though only to a small degree, through the 
agency of worms ; but their chief work is to 
sift the finer from the coarser particles, to 
mingle the whole with vegetable debris, and 
to saturate it with their intestinal secretions. 

Finally, no one who considers the facts 
given in this chapter-— on the burying of small 
objects and on the sinking of great stones left 
on the surface — on the vast number of worms 
which live within a moderate extent of ground 
— on the weight of the castings ejected from 
the mouth of the same burrow-— on the weight 
of all the castings ejected within a known time 
on a measured space — will hereafter, as I 
believe, doubt that worms play an important 
part in nature. 



1 64 BURIAL OF THE REMAINS CHAP. IV. 



CHAPTER IV. 

THE FART WHICH WORMS HAVE PLAYED IN 
THE BURIAL OF ANCIENT BUILDINGS. 

The accumulation of rubbish on the sites of gremt cities inde- 
pendent of the action of worms — The burial of a Roman 
villa at Abinger— The floors and walls penetrated by worms 
— Subsidence of a modem pavement— The buried pave- 
ment at Beaulieu Abbey — Roman villas at Chedworth and 
Brading— The remains of the Roman town at Silchester— 
The nature of the d^ris by which the remains are covered — 
The penetration of the tesselated floors and walls by worms 
— Subsidence of the floors— Thickness of the mould— The 
old Roman dty of Wroxeter— Thickness of the mould- 
Depth of the foundations of some of the Buildings— Con- 
clusion. 

Arch^ologists are probably not aware how 
much they owe to worms for the preservation 
of many ancient objects. Coins, gold orna- 
ments, stone implements, &c., if dropped on 
the surface of the ground, will infallibly be 
buried by the castings of worms in a few years, 
and will thus be safely preserved, until the 
land at some future time is turned up. For 
instance, many years ago a grass-field was 



CHAP. IV. OF ANCIENT BUILDINGS. 1 65 

ploughed on the northern side of the Severn, 
not far from Shrewsbury; and a surprising 
number of iron arrow-heads were found at the 
bottom of the furrows, which, as Mr. Blakeway, 
a local antiquary, believed, were relics of the 
battle of Shrewsbury in the year 1403, and no 
doubt had been originally left strewed on the 
battle-field. In the present chapter I shall 
show that not only implements, &c., are thus 
preserved, but that the floors and the remains 
of many ancient buildings in England have 
been buried so effectually, in large part through 
the action of worms, that they have been dis- 
covered in recent times solely through various 
accidents. The enormous beds of rubbish, 
several yards in thickness, which underlie many 
cities, such as Rome, Paris, and London, the 
lower ones being of great antiquity, are not 
here referred to, as they have not been in any 
way acted on by worms. When we consider 
how much matter is daily brought into a great 
city for building, fuel, clothing and food, and 
that in old times when the roads were bad 
and the work of the scavenger was neglected, 
a comparatively small amount was carried 
away, we may agree with Elie de Beaumont, 
who, in discussing this subject, says, " pour une 



1 66 BURIAL OF THE REMAINS CHAP. XV. 

^* voiture de mat^riaux qui en sort, on y en fait 
*'entrer cent"* Nor should we overlook the 
eflfects of fires, the demolition of old buildings, 
and the removal of rubbish to the nearest 
vacant space. 

AHnger, Surrey. — Late in the autumn of 
1876, the ground in an old farm-yard at this 
place was dug to a depth of 2 to 2\ feet, and 
the workmen found various ancient remains. 
This led Mr. T. H. Farrer of Abinger Hall 
to have an adjoining ploughed field searched. 
On a trench being dug, a layer of concrete, 
still partly covered with tesserae (small red 
tiles), and surrounded on two sides by broken- 
down walls, was soon discovered. It is be- 
lieved f that this room formed part of the 
atrium or reception-room of a Roman villa. 
The walls of two or three other small rooms 
were afterwards discovered. Many fragments 
of pottery, other objects, and coins of several 
Roman emperors, dating from 133 to 361, 
and perhaps to 375 a.d., were likewise found. 
Also a half-penny of George I., 1715. The 
presence of this latter coin seems an anomaly; 

* ' Lemons de G^Iogie pratique,' 1845, p. 142. 

t A short account of this discovery was published in ' The 
Times' of January 2, 1878; and a fuller account in 'The 
Builder,* January 5, 1878. 



CHAP. IV. OF ANCIENT BUILDINGS. 1 67 

but no doubt it was dropped on the ground 
during the last century, and since then there 
has been ample time for its burial under a 
considerable depth of the castings of worms. 
From the different dates of the Roman coins 
we may infer that the building was long in- 
habited It was probably ruined and deserted 
1400 or 1500 years ago. 

I was present during the commencement of 
the excavations (August 20, 1877) and Mr. 
Farrer had two deep trenches dug at opposite 
ends of the atrium, so that I might examine the ' 
nature of the soil near the remains. The field 
sloped from east to west at an angle of about 
7^ ; and one of the two trenches, shown in the 
accompanying section (Fig. 8) was at the upper 
or eastern end. The diagram is on a scale of 
^ of an inch to an inch ; but the trench, which 
was between 4 and 5 feet broad, and in parts 
above 5 feet deep, has necessarily been reduced 
out of all proportion. The fine mould over the 
floor of the atrium varied in thickness from 1 1 
to 16 inches ; and on the side of the trench in 
the section was a little over 13 inches. After 
the mould had been removed, the floor appeared 
as a whole moderately level ; but it sloped in 
parts at an angle of i^ and in one place near 



1 68 BURIAL OF THE REMAINS CHAP. IV. 

the outside at as much as 8^ 30'. The wall 
surrounding the pavement was built of rough 
stones, and was 23 inches in thickness where 
the trench was dug. Its broken summit was 
here 13 inches, but in another part 15 inches, 
beneath the surface of the field, being covered 
by this thickness of mould In one spot, how- 
ever, it rose to within 6 inches of the surface. 
On two. sides of the room, where the junction 
of the concrete floor with the bounding walls 
could be carefully examined, there was no crack 
or separation. This trench afterwards proved 
to have been dug within an adjoining room 
(11 ft. by II ft 6 in. in size), the existence of 
which was not even suspected whilst I was 
present 

On the side of the trench farthest from the 
buried wall (W), the mould varied from 9 to 14 
inches in thickness; it rested on a mass (B) 
23 inches thick of blackish earth, including 
many large stones. Beneath this was a thin 
bed of very black mould (C), then a layer of 
earth full of fragments of mortar (D), and then 
another thin bed (about 3 inches thick) (E) of 
very black mould, which rested on the undis« 
turbed subsoil (F) of firm, yellowish, argillace- 
ous sand. The 23-inch bed (B) was probably 




J ' * - 



CHAP. IV. OF ANCIENT BUILDINGS. 1 69 

made ground, as this would have brought up 
the floor of the room to a level with that of the 
atrium. The two thin beds of black mould at 
the bottom of the trench evidently marked two 
former land-surfaces. Outside the walls of the 
northern room, many bones, ashes, oyster-shells, 
broken pottery and an entire pot were subse- 
quently found at a depth of i6 inches beneath 
the surface. 

The second trench was dug on the western 
or lower side of the villa : the mould was here 
only 6^ inches in thickness, and it rested on a 
mass of fine earth full of stones, broken tiles 
and fragments of mortar, 34 inches in thickness, 
beneath which was the undisturbed sand. 
Most of this earth had probably been washed 
down from the upper part of the field, and the 
fragments of stones, tiles, &c., must have come 
from the immediately adjoining ruins. 

It appears at first sight a surprising fact 
that this field of light sandy soil should have 
been cultivated and ploughed during many 
years, and that not a vestige of these buildings 
should have been discovered. No one even 
suspected that the remains of a Roman villa lay 
hidden close beneath the surface. But the fact 
is less surprising when it is known that the field, 



170 BURIAL OF THE REMAINS CHAP. IV. 

as the bailiff believed, had never been ploughed 
to a greater depth than 4 inches. It is certain 
that when the land was first ploughed, the 
pavement and the surrounding broken walls 
must have been covered by at least 4 inches 
of soili for otherwise the rotten concrete floor 
would have been scored by the ploughshare, 
the tesserae torn up, and the tops of the old 
walls knocked down. 

When the concrete and tesserae were first 
cleared over a space of 14 by 9 ft, the floor 
which was coated with trodden-down earth 
exhibited no signs of having been penetrated 
by worms; and although the overlying fine 
mould closely resembled that which in many 
places has certainly been accumulated by 
worms, yet it seemed hardly possible that this 
mould could have been brought up by worms 
from beneath the apparently sound floor. It 
seemed also extremely improbable that the 
thick walls, surrounding the room and still 
united to the concrete, had been undermined 
by worms, and had thus been caused to sink, 
being afterwards covered up by their castings. 
I therefore at first concluded that all the fine 
mould above the ruins had been washed down 
from the upper parts of the field ; but we shall 



CHAP. IV. OF ANCIENT BUILDINGS. 1 71 

soon see that this conclusion was certainly 
erroneous^ though much fine earth is known to 
be washed down from the upper part of the 
field in its present ploughed state during heavy 
rauns. 

Although the concrete floor did not at first 
appear to have been anywhere penetrated by 
worms, yet by the next morning little cakes of 
the trodden-down earth had been lifted up 
by worms over the mouths of seven burrows, 
which passed through the softer parts of the 
naked concrete, or between the interstices of 
the tesserae. On the third morning twenty-five 
burrows were counted ; and by suddenly lifting 
up the little cakes of earth, four worms were 
seen in the act of quickly retreating. Two 
castings were thrown up during the third night 
on the floor, and these were of large size. The 
season was not favourable for the full activity 
of worms, and the weather had lately been hot 
and dry, so that most of the worms now lived 
at a considerable depth. In digging the two 
trenches many open burrows and some worms 
were encountered at between 30 and 40 inches 
beneath the surface ; but at a greater depth 
they became rare. One worm, however, was 
cut through at 48^, and another at 51^ inches 



172 BURIAL OF THE REMAINS CHAP. IV. 

beneath the surface. A fresh humus-lined 
burrow was also met with at a depth of 57 and 
another at 65^^ inches. At greater depths 
than this, neither burrows nor worms were 
seen. 

As I wished to learn how many worms 
lived beneath the floor of the atrium — a space 
of about 14 by 9 feet — Mr. Farrer was so kind 
as to make observations for me, during the 
next seven weeks, by which time the worms in 
the surrounding country were in full activity, 
and were working near the surface. It is very 
improbable that worms should have migrated 
from the adjoining field into the small space of 
the atrium, after the superficial mould in which 
they prefer to live, had been removed. We 
may therefore conclude that the burrows and 
the castings which were seen here during the 
ensuing seven weeks were the work of the 
former inhabitants of the space. I will now 
give a few extracts from Mr. Farrer's notes. 

Aug. 26th, 1877; that is, five days after 
the floor had been cleared. On the previous 
night there had been some heavy rain, which 
washed the surface clean, and now the mouths 
of forty burrows were counted. Parts of the 
concrete were seen to be solid, and had never 



CHAP. IV. OF ANCIENT BUILDINGS. 1 73 

been penetrated by worms, and here the rain- 
water lodged. 

Sept 5th. — Tracks of worms, made during 
the previous night, could be seen on the sur- 
face of the floor, and five or six vermiform cast- 
ings had been thrown up. These were defaced. 

Sept 1 2th. — During the last six days, the 
worms have not been active, though many 
castings have been ejected in the neighbour- 
ing fields; but on this day the earth was a 
little raised over the mouths of the burrows, 
or castings were ejected, at ten fresh points. 
These were defaced. It should be understood 
that when a fresh burrow is spoken of, this 
generally means only that an old burrow has 
been re-opened. Mr. Farrer was repeatedly 
struck with the pertinacity with which the 
worms re-opened their old burrows, even when 
no earth was ejected from them. I have 
often observed the same fact, and generally 
the mouths of the burrows are protected by 
an accumulation of pebbles, sticks or leaves. 
Mr. Farrer likewise observed that the worms 
living beneath the floor of the atrium often 
collected coarse grains of sand, and such little 
stones as they could find, round the mouths 
of their burrows. 



174 BURIAL OF THE REMAINS CHAP. IV, 

Sept. 13th ; soft wet weather. The mouths 
of the burrows were re-opened, or castings 
were ejected, at 31 points; these were all 
defaced. 

Sept. 14th; 34 fresh holes or castings; all 
defaced. 

Sept. 15th ; 44 fresh holes, only 5 castings ; 
all defaced. 

Sept. 1 8th; 43 fresh holes, 8 castings; all 
defaced. 

The number of castings on the surrounding 
fields was now very large. 

Sept 19th ; 40 holes, 8 castings ; all 
defaced. 

Sept. 22nd; 43 holes, only a few fresh 
castings ; all defaced. 

Sept 23rd ; 44 holes, 8 castings. 

Sept 25th; 50 holes, no record of the 
number of castings. 

Oct 13th; 61 holes, no record of the 
number of castings. 

After an interval of three years, Mr. Farrer, 
at my request, again looked at the concrete 
floor, and found the worms still at work. 

Knowing what great muscular power worms 
possess, and seeing how soft the concrete was 
in many parts, I was not surprised at its 



CHAP. IV. OF ANCIENT BUILDINGS. 175 

having been penetrated by their burrows; 
but it is a more surprising fact that the 
mortar between the rough stones of the thick 
walls, surrounding the rooms, was found by 
Mr. Farrer to have been penetrated by worms. 
On August 26th, that is, five days after the 
ruins had been exposed, he observed four 
open burrows on the broken summit of the 
eastern wall (W in Fig. 8) ; and, on September 
15th, other burrows similarly situated were 
seen. It should also be noted that in the 
perpendicular side of the trench (which was 
much deeper than is represented in Fig. 8) 
three recent burrows were seen, which ran 
obliquely far down beneath the base of the old 
wall. 

We thus see that many worms lived beneath 
the floor and the walls of the atrium at the 
time when the excavations were made ; and that 
they afterwards almost daily brought up earth 
to the surface from a considerable depth. There 
is not the slightest reason to doubt that worms 
have acted in this manner ever since the period 
when the concrete was sufficiently decayed to 
allow them to penetrate it; and even before 
that period they would have lived beneath the 
floor, as soon as it became pervious to rain, so 



176 BURIAL OF THE REMAINS CHAP. IV. 

that the soil beneath was kept damp. The 
floor and the walls must therefore have been 
continually undermined ; and fine earth must 
have been heaped on them during many 
centuriesi perhaps for a thousand years. If 
the burrows beneath the floor and walls, which 
it is probable were formerly as numerous as 
they now are, had not collapsed in the course 
of time in the manner formerly explained, the 
underlying earth would have been riddled with 
passages like a sponge; and as this was not 
the case, we may feel sure that they have 
collapsed. The inevitable result of such col- 
lapsing during successive centuries, will have 
been the slow subsidence of the floor and of 
the walls, and their burial beneath the accumu* 
lated worm-castings. The subsidence of a floor, 
whilst it still remains nearly horizontal, may at 
first appear improbable ; but the case presents 
no more real difficulty than that of loose objects 
strewed on the surface of a field, which, as we 
have seen, become buried several inches beneath 
the surface in the course of a few years, though 
still forming a horizontal layer parallel to the 
surface. The burial of the paved and level 
path on my lawn, which took place imder my 
own observation, is an analogous case. Even 



CHAP. IV. OF ANCIENT BUILDINGS. 1 77 

those parts of the concrete floor which the 
worms could not penetrate would almost 
certainly have been undermined, and would 
have sunk, like the great stones at Leith Hill 
Place and Stonehenge, for the soil would have 
been damp beneath them. But the rate of 
sinking of the different parts would not have 
been quite equal, and the floor was not quite 
level. The foundations of the boundary walls 
lie, as shown in the section, at a very small 
depth beneath the surface ; they would there- 
fore have tended to subside at nearly the same 
rate as the floor. But this would not have 
occurred if the foundations had been deep, 
as in the case of some other Roman ruins 
presently to be described. 

Finally, we may infer that a large part of 
the fine vegetable mould, which covered the 
floor and the broken-down walls of this villa, 
in some places to a thickness of i6 inches, was 
brought up from below by worms* From facts 
hereafter to be given there can be no doubt 
that some of the finest earth thus brought up 
will have been washed down the sloping surface 
of the field during every heavy shower of rain. 
If this had not occurred a greater amount of 
mould would have accumulated over the ruins 

N 



178 BURIAL OF THE REMAINS CHAP. IV. 

than that now present But beside the castings 
of worms and some earth brought up by insects, 
and some accumulation of dust, much fine earth 
will have been washed over the ruins from the 
upper parts of the field, since it has been under 
cultivation ; and from over the ruins to the 
lower parts of the slope ; the present thickness 
of the mould being the resultant of these several 
agencies. 

I may here append a modem instance of 
the sinking of a pavement, communicated to 
me in 1871 by Mr. Ramsay, Director of the 
Geological Survey of England. A passage 
without a roof, 7 feet in length by 3 feet 2 
inches in width, led from his house into the 
garden, and was paved with slabs of Portland 
stone. Several of these slabs were 16 inches 
square, others larger, and some a little smaller. 
This pavement had subsided about 3 inches 
along the middle of the passage, and two 
inches on each side, as could be seen by the 
lines of cement by which the slabs had been 
originally joined to the walls. The pavement 
had thus become slightly concave along the 
middle; but there was no subsidence at the 
end close to the house. Mr. Ramsay could 



CHAP. IV. OF ANCIENT BUILDINGS. 1 79 

not account for this sinking, until he observed 
that castings of black mould were frequently 
ejected along the lines of junction between 
the slabs; and these castings were regularly 
swept away. The several lines of junction, in- 
cluding those with the lateral walls, were 
altogether 39 feet 2 inches in length. The 
pavement did not present the appearance of 
ever having been renewed, and the house was 
believed to have been built about eighty-seven 
years ago. Considering all these circumstances, 
Mn Ramsay does not doubt that the earth 
brought up by the worms since the pavement 
was first laid down, or rather since the decay 
of the mortar allowed the worms to burrow 
through it, and therefore within a much shorter 
time than the eighty-seven years, has sufficed 
to cause the sinking of the pavement to the 
above amount, except close to the house, where 
the ground beneath would have been kept 
nearly dry. 

Beaulieu Abbey^ Hampshire. — This abbey 
was destroyed by Henry VI I L, and there now 
remains only a portion of the southern aisle- 
wall. It is believed that the king had most of 
the stones carried away for building a castle ; 
and it is certain that they have been removed. 



l8o BURIAL OF THE REMAINS CHAP. IV. 

The positions of the nave and transepts were 
ascertained not long ago by the foundations 
having been found ; and the place is now 
marked by stones let into the ground. Where 
the abbey formerly stood, there now extends a 
smooth grass-covered surface, which resembles 
in all respects the rest of the field. The 
guardian, a very old man, said the surface had 
never been levelled in his time. In the year 
1 8531 the Duke of Buccleuch had three holes 
dug in the turf within a few yards of one 
another, at the western end of the nave ; and 
the old tesselated pavement of the abbey was 
thus discovered These holes were afterwards 
surrounded by brickwork, and protected by 
trap-doors, so that the pavement might be 
readily inspected and preserved. When my 
son William examined the place on January 5, 
1872, he found that the pavement in the three 
holes lay at depths of 6|, 10 and 11^ inches 
beneath the surrounding turf-covered surface. 
The old guardian asserted that he was often 
forced to remove worm-castings from the pave- 
ment; and that he had done so about six 
months before. My son collected all from one 
of the holes, the area of which was 5*32 square 
feet, and they weighed 7*97 ounces. Assuming 



CHAP. IV. OF ANCIENT BUILDINGS. l8l 

that this amount had accumulated in six 
months, the accumulation during a year on a 
square yard would be 1*68 pounds, which, 
though a large amount, is very small compared 
with what, as we have seen, is often ejected on 
fields and commons. When I visited the 
abbey on June 22, 1877, the old man said that 
he had cleared out the holes about a month 
before, but a good many castings had since 
been ejected. I suspect that he imagined that 
he swept the pavements oftener than he really 
did, for the conditions were in several respects 
very unfavourable for the accumulation of even 
a moderate amount of castings. The tiles are 
rather large, viz., about 5^ inches square, and 
the mortar between them was in most places 
sound) so that the worms were able to bring up 
earth from below only at certain points. The 
tiles rested on a bed of concrete, and the cast- 
ings in consequence consisted in large part 
(viz., in the proportion of 19 to 33) of particles 
of mortar, grains of sand, little fragments of 
rock, bricks or tile ; and such substances could 
hardly be agreeable, and certainly not nutri- 
tious, to worms. 

My son dug holes in several places within 
the former walls of the abbey, at a distance of 



1 82 BURIAL OF THE REMAINS CHAP. IV. 

several yards from the above described bricked 
squares. He did not find any tiles, though 
these are known to occur in some other parts, 
but he came in one spot to concrete on which 
tiles had once rested. The fine mould beneath 
the turf on the sides of the several holes, 
varied in thickness from only a to 2| inches, 
and this rested on a layer from 8| to above 1 1 
inches in thickness, consisting of fragments of 
mortar and stone-rubbish with the interstices 
compactly filled up with black mould. In the 
surrounding field, at a distance of 20 yards 
from the abbey, the fine vegetable mould was 
1 1 inches thick. 

We may conclude from these facts that 
when the abbey was destroyed and the stones 
removed, a layer of rubbish was left over the 
whole surface, and that as soon as the worms 
were able to penetrate the decayed concrete 
and the joints between the tfles, they slowly 
filled up the interstices in the overlying rubbish 
with their castings, which were afterwards 
accumulated to a thickness of nearly three 
inches over the whole surface. If we add 
to this latter amount the mould between the 
fragments of stones, some five or six inches 
of mould must have been brought up from 



CHAP. IV. OF ANCIENT BUILDINGS. 1 83 

beneath the concrete or tiles. The concrete 
or tiles will consequently have subsided to 
nearly this amount The bases of the 
columns of the aisles are now buried beneath 
mould and turf. It is not probable that 
they can have been undermined by worms* 
for their foundations would no doubt have 
been laid at a considerable depth. If they 
have not subsided, the stones of which the 
columns were constructed must have been 
removed from beneath the former level of 
the floor. 

Chedwarth^ Gloucestershire. — The remains 
of a large Roman villa were discovered here 
in 1866, on ground which had been covered 
with wood from time immemorial. No 
suspicion seems ever to have been entertained 
that ancient buildings lay buried here, 
until a gamekeeper, in digging for rabbits, 
encountered some remains.^ But subse- 
quently the tops of some stone walls were 
detected in parts of the wood, projecting a 



* Several accounts of these ruins have been published ; the 
best is by Mr. James Farrer in ^Proc. Soc. of Antiquaries of 
Scotland,' vol vL, Part II., 1867, p. 278. Also J. W. Groveri 
'Journal of the British Arch. Assoc.' June 1866. Professor 
Buckman has likewise published a pamphlet, ' Notes on the 
Roman Villa at Chedworth,' 2nd edit. 1873 : Cirencester. 



184 BURIAL OF THE REMAINS CHAP. IV. 

little above the surface of the ground. Most 
of the coins found here belonged to Constans 
(who died 350 a.d.) and the Constantine family. 
My sons Francis and Horace visited the 
place in November 1877, for the sake of 
ascertaining what part worms may have 
played in the burial of these extensive remains. 
But the circumstances were not favourable for 
this object, as the ruins are surrounded on 
three sides by rather steep banks, down which 
earth is washed during rainy weather. More- 
over most of the old rooms have been covered 
with roofs, for the protection of the elegant 
tesselated pavements. 

A few facts may, however, be given on the 
thickness of the soil over these ruins. Close 
outside the northern rooms there is a broken 
wall, the summit of which was covered by 5 
inches of black mould ; and in a hole dug on 
the outer side of this wall, where the ground 
had never before been disturbed, black mould, 
full of stones, 26 inches in thickness, was 
found, resting on the undisturbed sub-soil of 
yellow day. At a depth of 2 a inches from 
the surface a pig's jaw and a fragment of a 
tile were found. When the excavations were 
first made, some large trees grew over the 



CHAP. IV, OF ANCIENT BUILDINGS. 1 85 

ruins; and the stump of one has been left 
directly over a party-wall near the bath-room, 
for the sake of showing the thickness of 
the superincumbent soil, which was here 
38 inches. In one small room, which, after 
being cleared out, had not been roofed over, 
my sons observed the hole of a worm passing 
through the rotten concrete, and a living 
worm was found within the concrete. In 
another open room worm-castings were seen 
on the floor, over which some earth had by 
this means been deposited, and here grass 
now grew. 

Brading^ Isle of Wight. — A fine Roman 
villa was discovered here in 1880; and by 
the end of October no less than i8 chambers 
had been more or less cleared. A coin dated 
337 A.D. was found. My son William visited 
the place before the excavations were com- 
pleted ; and he informs me that most of the 
floors were at first covered with much rubbish 
and fallen stones, having their interstices 
completely filled up with mould, abounding, 
as the workmen said, with worms, above 
which there was mould without any stones. 
The whole mass was in most places from 3 
to above 4 ft in thickness. In one very 



1 86 BURIAL OF THE REMAINS. CHAP. IV. 

large room the overlying earth was only 
2 ft 6 in. thick; and after this had been 
removed, so many castings were thrown up 
between the tiles that the surface had to 
be almost daily swept Most of the floors 
were fairly level. The tops of the broken- 
down walls were covered in some places by 
only 4 or 5 inches of soil, so that they 
were occasionally struck by the plough, but 
in other places they were covered by from 13 
to 18 inches of soil. It is not probable that 
these walls could have been undermined by 
worms and subsided, as they rested on a 
foundation of very hard red sand, into which 
worms could hardly burrow. The mortar, 
however, between the stones of the walls of 
a hypocaust was found by my son to have 
been penetrated by many worm-burrows. 
The remains of this villa stand on land which 
slopes at an angle of about 3^ ; and the land 
appears to have been long cultivated There- 
fore no doubt a considerable quantity of fine 
earth has been washed down from the upper 
parts of the field, and has largely aided in 
the burial of these remains. 

Silchester, Hampshire. — The ruins of this 
small Roman town have been better preserved 



Gms 



w 



:--.'.«^ 




Fig. 7.— Section through one of the fallen Dniidical stones at Stonehenge, 
showing how much it had sunk into the ground. Scale ^ inch to i foot. 



•6 



J-S 






- * 






J « 



C/5 



I 



•5 

C 

o 

I 






[To /ace p. 186. 



CHAP.nr. OF ANCIENT BUILDINGS. 1 87 

than any other remains of the kind in England. 
A broken wall, in most parts from 15 to 18 
feet in height and about i^ mile in compass, 
now surrounds a space of about 100 acres of 
cultivated land, on which a farm-house and a 
church stand.* Formerly, when the weather 
was dry, the lines of the buried walls could be 
traced by the appearance of the crops; and 
recently very extensive excavations have been 
undertaken by the Duke of Wellington, under 
the superintendence of the late Rev. J. G. 
Joyce, by which means many large buildings 
have been discovered. Mr. Joyce made careful 
coloured sections, and measured the thickness 
of each bed of rubbish, whilst the excavations 
were in progress ; and he has had the kindness 
to send me copies of several of them. When 
my sons Francis and Horace visited these 
ruins, he accompanied them, and added his 
notes to theirs. 

Mr. Joyce estimates that the town was 
inhabited by the Romans for about three 
centuries ; and no doubt much matter must 
have accumulated within the walls during 
this long period. It appears to have been 

* These details are taken from the * Penny Cyclopaedia,' 
article Hampshire. 



1 88 BURIAL OF THE REMAINS CHAP. IV. 

destroyed by fire, and most of the stones used 
in the buildings have since been carried away. 
These circumstances are unfavourable for as- 
certaining the part which worms have played 
in the burial of the ruins; but as careful 
sections of the rubbish overlying an ancient 
town have seldom or never before been made 
in England, I will give copies of the most 
characteristic portions of some of those made 
by Mr. Joyce. They are of too great length 
to be here introduced entire. 

An east and west section, 30 ft. in length, 
was made across a room in the Basilica, now 
called the Hall of the Merchants (Fig. 9). 
The hard concrete floor, still covered here and 
there with tesserae, was found at 3 ft. beneath 
the surface of the field, which was here level. 
On the floor there were two large piles of 
charred wood, one alone of which is shown in 
the part of the section here given. This pile 
was covered by a thin white layer of decayed 
stucco or plaster, above which was a mass, 
presenting a singularly disturbed appearance, 
of broken tiles, mortar, rubbish and fine gravel, 
together 27 inches in thickness. Mr. Joyce 
believes that the gravel was used in making 
the mortar or concrete, which has since 



CHAP. IV. OF ANCIENT BUILDINGS. 1 89 

decayed, some of the lime probably having been 
dissolved. The disturbed state of the rubbish 
may have been due to its having been searched 
for building stones. This bed was capped by 
fine vegetable mould, 9 inches in thickness. 
From these facts we may conclude that the 
Hall was burnt down, and that much rubbish 
fell on the floor, through and from which the 
worms slowly brought up the mould, now 
forming the surface of the level field. 

A section across the middle of another hall 
in the Basilica, 32 feet 6 inches in length, 
called the iCrarium, is shown in Fig. la It 
appears that we have here evidence of two 
fires, separated by an interval of time, during 
which the 6 inches of ''mortar and concrete 
with broken tiles " was accumulated. Beneath 
one of the layers of charred wood, a valuable 
relic, a bronze eagle, was found; and this 
shows that the soldiers must have deserted the 
place in a panic. Owing to the death of Mr. 
Joyce, I have not been able to ascertain 
beneath which of the two layers the eagle was 
found. The bed of rubble overlying the un- 
disturbed gravel originally formed, as I suppose, 
the floor, for it stands on a level with that of a 
corridor, outside the walls of the Hall ; but the 



IQO BURIAL OF THE REMAINS CHAP. IV 

corridor is not shown in the section as here 
given. The v^^etable mould was i6 inches 
thick in the thickest part ; and the depth from 
the surface of the field, clothed with herbage, 
to the undisturbed gravel* was 40 inches. 

The section shown in Fig. 1 1 represents an 
excavation made in the middle of the town, 
and is here introduced because the bed of 
** rich mould " attained, according to Mr. Joyce, 
the unusual thickness of 20 inches. Gravel 
lay at the depth of 48 inches from the surface ; 
but it was not ascertained whether this was in 
its natural state, or had been brought here and 
had been rammed down, as occurs in some 
other places. 

The section shown in Fig. 12 was taken 
in the centre of the Basilica, and though it 
was 5 feet in depth, the natural sub-soil was 
not reached. The bed marked " concrete'* 
was probably at one time a floor; and the 
beds beneath seem to be the remnants of more 
ancient buildings. The v^etable mould was 
here only 9 inches thick. In some other 
sections, not copied, we likewise have evidence 
of buildings having been erected over the 
ruins of older ones. In one case there was a 
layer of yellow clay of very unequal thickness 




Mould, 20 inches 
thick. 



Rubble with broken 
tiles, 4 inches thick. 



Black decayed wood, 
in thickest part 6 
inches thick. 



Gravel. 



Fig. II. — Section in a block of buildings in the middle of the town of 
Silchester. 

\Jo/ace p. 190. 



CHAP. IV. OF ANCIENT BUILDINGS. I9I 

between two beds of d^brb, the lower one of 
which rested on a floor with tesserae. The 
ancient broken walls appear to have been 
sometimes roughly cut down to a uniform 
level, so as to serve as the foundations for a 
temporary building; and Mr. Joyce suspects 
that some of these buildings were wattled 
sheds, plastered with clay, which would account 
for the above-mentioned layer of clay. 

Turning now to the points which more 
immediately concern us. Worm-castings were 
observed on the floors of several of the rooms, 
in one of which the tesselation was unusually 
perfect The tesserae here consisted of little 
cubes of hard sandstone of about i inch, 
several of which were loose or projected 
slightly above the general level One or 
occasionally two open worm-burrows were 
found beneath all the loose tesserae. Worms 
have also penetrated the old walls of these 
ruins. A wall, which had just been exposed 
to view during the excavations then in pro- 
gress, was examined; it was built of large 
flints, and was i8 inches in thickness. It 
appeared sound, but when the soil was re- 
moved from beneath, the mortar in the lower 
part was found to be so much decayed that the 



192 BURIAL OF THE REMAINS CHAP. IV. 

flints fell apart from their own weight. Here, 
in the middle of the wall, at a depth of 29 
inches beneath the old floor and of 49^ inches 
beneath the surface of the field, a living worm 
was found, and the mortar was penetrated by 
several burrows. 

A second wall was exposed to view for the 
first time, and an open burrow was seen on 
its broken summit By separating the flints 
this burrow was traced far down in the in- 
terior of the wall ; but as some of the flints 
cohered firmly, the whole mass was disturbed 
in pulling down the wall, and the burrow 
could not be traced to the bottom. The 
foundations of a third wall, which appeared 
quite sound, lay at a depth of 4 feet beneath 
one of the floors, and of course at a consider- 
ably greater depth beneath the level of the 
ground. A large flint was wrenched out of 
the wall at about a foot from the base, and 
this required much force, as the mortar was 
sound ; but behind the flint in the middle of 
the wall, the mortar was friable, and here there 
were worm-burrows. Mr. Joyce and my sons 
were surprised at the blackness of the mortar 
in this and in several other cases, and at the 
presence of mould in the interior of the walls. 
















^S^<-^^ 



Mould, 9 inches thick. 



Light-coloured earth with 
large pieces of broken 
lil^, 7 inches. 



Dark, fine-grained rubbi^>h 
with small bits of tiles, 30 
inches. 



Concrete, 4 inches 
Stucco, 2 inches. 



Made bottom with frag- 
ment of tiles, 8 inches. 



Fine-grained made ground, 
with the debris of older 
buildings. 



Fig. 12. —Section ia the centre of the Basilica at Silchester. 

Uofacep, 19a. 



CHAP. IV. OF ANCIENT BUILDINGS. 1 93 

Some may have been placed there by the old 
builders instead of mortar; but we should 
remember that worms line their burrows with 
black humus. Moreover open spaces would 
almost certainly have been occasionally left 
between the large irregular flints ; and these 
spaces, we may feel sure, would be filled up by 
the worms with their castings, as soon as they 
were able to penetrate the wall. Rain-water, 
oozing down the burrows would also carry 
fine dark-coloured particles into every crevice. 
Mr. Joyce was at first very sceptical about the 
amount of work which I attributed to worms ; 
but he ends his notes with reference to the 
last-mentioned wall by saying, ''This case 
''caused me more surprise and brought more 
" conviction to me than any other. I should 
''have said, and did say, that it was quite 
"impossible such a wall could have been 
" penetrated by earth-worms.'' 

In almost all the rooms the pavement 
has sunk considerably, especially towards the 
middle ; and this is shown in the three follow- 
ing sections. The measurements were made 
by stretching a string tightly and horizontally 
over the floor. The section, Fig. 13, was 
taken from north to south across a room, 

o 



194 BURIAL OF THE REMAINS CHAP. IV. 

1 8 feet 4 inches in length, with a nearly perfect 
pavement, next to the "Red Wooden Hut" 
In the northern half, the subsidence amounted 
to 5l inches beneath the level of the floor as 
it now stands close to the walls; and it was 
greater in the northern than in the southern 
half; but, according to Mr. Joyce, the entire 
pavement has obviously subsided. In several 
places, the tesserae appeared as if drawn a 
little away from the walls; whilst in other 
places they were still in close contact with 
them. 

In Fig. 14, we see a section across the 
paved floor of the southern corridor or ambula- 
tory of a quadrangle, in an excavation made 
near "The Spring." The floor is 7 feet 9 
inches wide, and the broken-down walls now 
project only J of an inch above its level. The 
field, which was in pasture, here sloped from 
north to south, at an angle of 3** 40'. The 
nature of the ground at some little distance 
on each side of the corridor is shown in the 
section. It consisted of earth full of stones 
and other debris, capped with dark vegetable 
mould which was thicker on the lower or 
southern than on the northern side. The 
pavement was nearly level along lines parallel 





43 

•8 



* 







CHAP. IV. OF ANCIENT BUILDINGS. I95 

to the side-walls, but had sunk in the middle 
as much as 7I inches. 

A small room at no great distance from 
that represented in Fig. 13, had been enlarged 
by the Roman occupier on the southern side, 
by an addition of 5 feet 4 inches in breadth. 
For this purpose the southern wall of the 
house had been pulled down, but the founda- 
tions of the old wall had been left buried at 
a little depth beneath the pavement of the 
enlarged room. Mr. Joyce believes that this 
buried wall must have been built before the 
reign of Claudius IL, who died 270 a.d. We 
see in the accompanying section, Fig. 15, that 
the tesselated pavement has subsided to a less 
degree over the buried wall than elsewhere; 
so that a slight convexity or protuberance here 
stretched in a straight line across the room. 
This led to a hole being dug, and the buried 
wall was thus discovered. 

We see in these three sections, and in 
several others not given, that the old pave- 
ments have sunk or sagged considerably. Mr. 
Joyce formerly attributed this sinking solely 
to the slow settling of the ground. That there 
has been some settling is highly probable, 
and it may be seen in Fig. 15 that the 



196 BURIAL OF THE REMAINS CHAP. IV. 

pavement for a width of 5 feet over the southern 
enlargement of the room, which must have 
been built on fresh ground, has sunk a little 
more than on the old northern side. But this 
sinking may possibly have had no connection 
with the enlaigement of the room ; for in 
Fig. 13 one half of the pavement has subsided 
more than the other half without any assign- 
able cause. In a bricked passage to Mr. 
Joyce's own house, laid down only about six 
years ago, the same kind of sinking has 
occurred as in the ancient buildings. Never- 
theless it does not appear probable that the 
whole amount of sinking can be thus accounted 
for. The Roman builders excavated the 
ground to an unusual depth for the foundations 
of their walls, which were thick and solid ; it 
is therefore hardly credible that they should 
have been careless about the solidity of the 
bed on which their tesselated and often 
ornamented pavements were laid. The sinking 
must, as it appears to me, be attributed in 
chief part to the pavement having been under- 
mined by worms, which we know are still at 
work. Even Mr. Joyce at last admitted that 
this could not have failed to have produced 
a considerable effect. Thus also the large 




JJ V 



CHAP. IV. OF ANCIENT BUILDINGS. I97 

quantity of fine mould overlying the pavements 
can be accounted for, the presence of which 
would otherwise be inexplicable. My sons 
noticed that in one room in which the pave- 
ment had sagged very little, there was an 
unusually small amount of overlying mould. 

As the foundations of the walls generally 
lie at a considerable depth, they will either 
have not subsided at all through the under* 
mining action of worms, or they will have 
subsided much less than the floor. This latter 
result would follow from worms not often 
working deep down beneath the foundations; 
but more especially from the walls not yield- 
ing when penetrated by worms, whereas the 
successively formed burrows in a mass of 
earth, equal to one of the walls in depth and 
thickness, would have collapsed many times 
since the desertion of the ruins, and would 
consequently have shrunk or subsided. As 
the walls cannot have sunk much or at all, 
the immediately adjoining pavement from 
adhering to them will have been prevented 
from subsiding ; and thus the present curvature 
of the pavement is intelligible. 

The circumstance which has surprised me 
most with respect to Silchester is that during 



198 BURIAL OF THE REMAINS CHAP. IV. 

the many centuries which have elapsed since 
the old buildings were deserted, the vegetable 
mould has not accumulated over them to a 
greater thickness than that here observed. In 
most places it is only about 9 inches in thick- 
ness, but in some places 12 or even more 
inches. In Fig. 11, it is given as 20 inches, 
but this section was drawn by Mr. Joyce 
before his attention was particularly called to 
this subject The land enclosed within the 
old walls is described as sloping slightly to 
the south ; but there are parts which, accord- 
ing to Mr. Joyce, are nearly level, and it 
appears that the mould is here generally 
thicker than elsewhere. The surface slopes 
in other parts from west to cast, and Mr. Joyce 
describes one floor as covered at the western 
end by rubbish and mould to a thickness of 
28^ inches, and at the eastern end by a thick- 
ness of only II J inches. A very slight slope 
suffices to cause recent castings to flow down- 
wards during heavy rain, and thus much earth 
will ultimately reach the neighbouring rills 
and streams and be carried away. By this 
means, the absence of very thick beds of 
mould over these ancient ruins may, as I 
believe, be explained. Moreover most of 



CHAP. IV. OF ANCIENT BUILDINGS. 1 99 

the land here has long been ploughed, and 
this would greatly aid the washing away of 
the finer earth during rainy weather. 

The nature of the beds immediately beneath 
the vegetable mould in some of the sections 
is rather perplexing. We see, for instance, in 
the section of an excavation in a grass meadow 
(Fig. 14), which sloped from north to south 
at an angle of 3"" 40', that the mould on the 
upper side is only six inches and on the lower 
side nine inches in thickness. But this mould 
lies on a mass (25^ inches in thickness on the 
upper side) "of dark brown mould," as 
described by Mr. Joyce, " thickly interspersed 
"with small pebbles and bits of tiles, which 
"present a corroded or worn appearance." 
The state of this dark-coloured earth is like 
that of a field which has long been ploughed, 
for the earth thus becomes intermingled with 
stones and fragments of all kinds which have 
been much exposed to the weather. If during 
the course of many centuries this grass meadow 
and the other now cultivated fields have been 
at times ploughed, and at other times left as 
pasture, the nature of the ground in the above 
section is rendered intelligible. For worms 
will continually have brought up fine earth 



200 BURIAL OF THE REMAINS CHAP. IV. 

from belowi which will have been stirred up 
by the plough whenever the land was culti- 
vated. But after a time a greater thickness 
of fine earth will thus have been accumulated 
than could be reached by the plough ; and 
a bed like the 25^-inch mass, in Fig. 14, will 
have been formed beneath the superficial 
mouldy which latter will have been brought to 
the surface within more recent times, and have 
been well sifted by the worms. 

Wroxeter^ Shropshire. — The old Roman 
city of Uriconium was founded in the early 
part of the second century, if not before this 
date ; and it was destroyed, according to Mr. 
Wright, probably between the middle of the 
fourth and fifth century. The inhabitants 
were massacred, and skeletons of women were 
found in the hypocausts. Before the year 
1859, the sole remnant of the city above 
ground, was a portion of a massive wall about 
20 ft in height The surrounding land 
undulates slightly, and has long been under 
cultivation. It had been noticed that the 
corn-crops ripened prematurely in certain 
narrow lines, and that the snow remained 
unmelted in certain places longer than in 
others. These appearances led, as I was 



CHAP. IV. OF ANaENT BUILDINGS. 20I 

informed, to extensive excavations being under- 
taken. The foundations of many large buildings 
and several streets have thus been exposed to 
view. The space enclosed within the old walls 
is an irregular oval, about if mile in length. 
Many of the stones or bricks used in the 
buildings must have been carried away; but 
the hypocaustSy baths, and other underground 
buildings were found tolerably perfect, being 
filled with stones, broken tiles, rubbish and 
soil. The old floors of various rooms were 
covered with rubble. As I was anxious to 
know how thick the mantle of mould and 
rubbish was, which had so long concealed 
these ruins, I applied to Dr. H. Johnson, who 
had superintended the excavations; and he, 
with the greatest kindness, twice visited the 
place to examine it in reference to my ques- 
tions, and had many trenches dug in four 
fields which had hitherto been undisturbed. 
The results of his observations are given in 
the following Table. He also sent me speci- 
mens of the mould, and answered, as far as he 
could, all my questions. 



202 BURIAL OF THE REMAINS CHAP. IV. 



MEASUREBiSNTS BY DR. H. JOHNSON OF THE THICKNESS OF 

the vegetable mould over the roman ruins at 
Wroxster. 

Trenches dug in a field called " Old Works/' 

TUckiMsg 
ofmookliii 



1. At a depth of 36 inches tmdistarbed sand was 

reached 20 

2. At a depth of 33 inches concrete was reached 21 

3. ,, f, 9 inches concrete was reached 9 

Trenches dug in a field called ''Shop 
Leasows ; '' this is the highest field within the 
old walls, and slopes down from a sub-central 
point on all sides at about an angle of 2"". 

Thickness 
ofmooldia 



4. Summit of field, trench 45 inches deep .. 40 

5. Close to sunmit of field, trench 36 inches deep 26 

6. ,, „ trench 28 inches deep 28 
7* Near summit of field, trench 36 inches deep .. 24 

8. ,, I, trench at one end 39 
inches deep ; the mould here graduated into 
the underlying undisturbed sand, and its 
thickness (24 inches) is somewhat arbitrary. 
At the other end of the trench, a causeway 
was encountered at a depth of only 7 inches, 
and the mould was here only 7 inches thick 24 

9. Trench close to the last, 28 inches in depth .. 15 
la Lower part of same field, trench 30 inches deep 15 

11. „ „ trench 31 inches deep 17 

12. „ „ trench 36 bches deep, 

at which depth undisturbed sand was reached 28 

13. In another part of same fiekl, trench 9^ inches 

deep stopped by concrete 9^ 



CHAP. IV. OF ANaENT BUILDINGS. 2O3 



ThickiMtB 
ofmooldin 



14. In another part of same field, trench 9 inches 

deep, stopped by concrete 9 

15. In another part of the same field, trench 24 

inches deep, when sand was reached 16 

16. In another part of same field, trench 30 inches 

deep, when stones were reached ; at one end 
of the trench mould 12 inches, at the other 
end 14 inches thick 13 

Small field between "Old Works'* and 
" Shop Leasows/* I believe nearly as high as 
the upper part of the latter field 

Thickness 
ofoKMildin 



17. Trench 26 inches deep 24 

18. „ 10 inches deep, and then came upon a 
causeway 10 

19. Trench 34 inches deep 30 

2a „ 31 inches deep 31 

Field on the western side of the space 
enclosed within the old walls. 

ThickiMM 
of moaldiii 



21. Trench 28 inches deep, when undisturbed sand 

was reached 16 

22. Trench 29 inches deep, when undisturbed sand 

was reached 1$ 

23. Trench 14 inches deep, and then came upon a 

building 14 

Dn Johnson distinguished as mould the 
earth which differed^ more or less abruptly, in 
its dark colour and in its texture from the 



204 BURIAL OF THE REMAINS CHAP. IV. 

underlying sand or rubble. In the specimens 
sent to me, the mould resembled that which 
lies immediately beneath the turf in old 
pasture-land, excepting that it often contained 
small stones, too large to have passed through 
the bodies of worms. But the trenches above 
described were dug in fields, none of which 
were in pasture, and all had been long culti- 
vated. Bearing in mind the remarks made in 
reference to Silchester on the effects of long- 
continued culture, combined with the action of 
worms in bringing up the finer particles to the 
surface, the mould, as so designated by Dr. 
Johnson, seems fairly well to deserve its name. 
Its thickness, where there was no causeway, 
floor or walls beneath, was greater than has 
been elsewhere observed, namely, in many 
places above 2 ft, and in one spot above 3 ft. 
The mould was thickest on and close to the 
nearly level summit of the field called ** Shop 
Leasows,*' and in a small adjoining field, 
which, as I believe, is of nearly the same 
height One side of the former field slopes 
at an angle of rather above 2"", and I should 
have expected that the mould, from being 
washed down during heavy rain, would have 
been thicker in the lower than in the upper 



CHAP. IV. OF ANCIENT BUILDINGS. 205 

part ; but this was not the case in two out of 
the three trenches here dug. 

In many places, where streets ran beneath 
the surface, or where old buildings stood, the 
mould was only 8 inches in thickness; and 
Dr. Johnson was surprised that in ploughing 
the land, the ruins had never been struck by 
the plough as far as he had heard He thinks 
that when the land was first cultivated the old 
walls were perhaps intentionally pulled down, 
and that hollow places were filled up. This 
may have been the case; but if after the 
desertion of the city the land was left for many 
centuries uncultivated, worms would have 
brought up enough fine earth to have covered 
the ruins completely.; that is if they had 
subsided from having been undermined. The 
foundations of some of the walls, for instance 
those of the portion still standing about 20 feet 
above the ground, and those of the market- 
place, lie at the extraordinary depth of 14 feet ; 
but it is highly improbable that the founda- 
tions were generally so deep. The mortar 
employed in the buildings must have been 
excellent, for it is still in parts extremely hard. 
Wherever walls of any height have been ex- 
posed to view, they are, as Dr. Johnson 



206 BURIAL OF THE REMAINS CHAP. IV. 

believes, still perpendicular. The walls with 
such deep foundations cannot have been under- 
mined by worms, and therefore cannot have 
subsided, as appears to have occurred at 
Abinger and Silchester. Hence it is very 
difficult to account for their being now com- 
pletely covered with earth; but how much 
of this covering consists of vegetable mould 
and how much of rubble I do not know. The 
market-place, with the foundations at a depth 
of 14 feet, was covered up, as Dr. Johnson 
believes, by between 6 and 24 inches of earth. 
The tops of the broken-down walls of a 
caldarium or bath, 9 feet in depth, were like- 
wise covered up with nearly 2 feet of earth. 
The summit of an arch, leading into an ash- 
pit 7 feet in depth, was covered up with not 
more than 8 inches of earth. Whenever a 
building which has not subsided is covered 
with earth, we must suppose^ either that the 
upper layers of stone have been at some time 
carried away by man, or that earth has since 
been washed down during heavy rain, or 
blown down during storms, from the adjoining 
land ; and this would be especially apt to 
occur where the land has long been cultivated. 
In the above cases the adjoining land is 



CHAP. IV. OF ANCIENT BUILDINGS. '^0^ 

somewhat higher than the three specified sites, 
as far as I can judge by maps and from informa- 
tion given me by Dr. Johnson. If, however, 
a great pile of broken stones, mortar, plaster, 
timber and ashes fell over the remains of any 
building, their disintegration in the course of 
time, and the sifting action of worms, would 
ultimately conceal the whole beneath fine earth. 

Conclusion. — The cases given in this chapter 
show that worms have played a considerable 
part in the burial and concealment of several 
Roman and other old buildings in England; 
but no doubt the washing down of soil from 
the neighbouring higher lands, and the de- 
position of dust, have together aided largely 
in the work of concealment. Dust would be 
apt to accumulate wherever old broken-down 
walls projected a little above the then exist- 
ing surface and thus afforded some shelter. 
The floors of the old rooms, halls and passages 
have generally sunk, partly from the settling 
of the ground, but chiefly from having been 
undermined by worms; and the sinking has 
commonly been greater in the middle than 
near the walls. The walls themselves, when- 
ever their foundations do not lie at a great 



2o8 BURIAL OF ANCIENT BUILDINGS. CHAP. IV. 

depths have been penetrated and undermined 
by worms, and have consequently subsided. 
The unequal subsidence thus caused, probably 
explains the great cracks which may be seen 
in many ancient walls, as well as their inclina- 
tion from the perpendicular. 



( 209 ) 



CHAPTER V. 

THE ACTION OF WORMS IN THE DENUDATION 
OF THE LAND. 

Evidence of the amount of denudation which the land has 
undergone — Sub-aerial denudation— The deposition of 
dust — ^Vegetable mould, its dark colour and fine texture 
largely due to the action of worms— The disintegration of 
rocks by the humus-acids — Similar acids apparently 
generated within the bodies of worms — The action of 
these acids facilitated by the continued movement of the 
particles of earth — A thick bed of mould checks the dis- 
integration of the underlying soil and rocks. Particles of 
stone worn or triturated in the gizzards of worms — 
Swallowed stones serve as mill-stones — The levigated 
state of the castings — ^Fragments of brick in the castings 
over ancient buildings well rounded. The triturating 
power of worms not quite insignificant under a geological 
point of view. 

No One doubts that our world at one time 
consisted of crystalline rocks, and that it is to 
their disintegration through the action of air, 
water, changes of temperature, rivers, waves 
of the sea, earthquakes and volcanic outbursts, 
that we owe our sedimentary formations. 
These after being consolidated and some- 
times recrystallized, have often been again 

p 



2 1 DISINTEGRATION CHAP. v. 

disintegrated. Denudation means the removal 
of such disintegrated matter to a lower level. 
Of the many striking results due to the modem 
progress of geology there are hardly any 
more striking than those which relate to 
denudation. It was long ago seen that there 
must have been an immense amount of de- 
nudation; but until the successive formations 
were carefully mapped and measured, no one 
fully realised how great was the amount One 
of the first and most remarkable memoirs ever 
published on this subject was that by Ramsay,* 
who in 1846 showed that in Wales from 9000 
to 11,000 feet in thickness of solid rock had 
been stripped off large tracks of country. 
Perhaps the plainest evidence of great de- 
nudation is afforded by faults or cracks, which 
extend for many miles across certain districts, 
with the strata on one side raised even ten 
thousand feet above the corresponding strata 
on the opposite side; and yet there is not a 
vestige of this gigantic displacement visible 
on the surface of the land. A huge pile of 
rock has been planed away on one side and 
not a remnant left 

* " On the denudation of South Wales," &c., * Memoirs of 
the Geological Survey of Great Britain,' vol. i., p. 297, 1846. 



CHAP.V. AND DENUDATION. 211 

Until the last twenty or thirty years, most 
geologists thought that the waves of the sea 
were the chief agents in the work of denuda- 
tion; but we may now feel sure that air and 
rain, aided by streams and rivers, are much 
more powerful agents, — that is if we consider 
the whole area of the land The long lines of 
escarpment which stretch across several parts 
of England were formerly considered to be 
undoubtedly ancient coast-lines; but we now 
know that they stand up above the general 
surface merely from resisting air, rain and 
frost better than the adjoining formations. It 
has rarely been the good fortune of a geologist 
to bring conviction to the minds of his fellow- 
workers on a disputed point by a single 
memoir ; but Mr. Whitaker, of the Geological 
Survey of England, was so fortunate when, in 
1867, ^^ published his paper ** On sub-aerial 
Denudation, and on Cliffs and Escarpments 
of the Chalk." * Before this paper appeared, 
Mr. A. Tylor had adduced important evidence 
on sub-aerial denudation, by showing that the 
amount of matter brought down by rivers must 

* * Geological Magazine,' October and November, 1867, vol. 
iv. pp. 447 and 483. Copious references on the subject are 
given in this remarkable memoir. 



2 1 2 DISINTEGRATION CHAP. v. 

infallibly lower the level of their drainage- 
basins by many feet in no immense lapse of 
time. This line of argument has since been 
followed up in the most interesting manner 
by Archibald Geikie, CroU and others, in a 
series of valuable memoirs.* For the sake of 
those who have never attended to this subject, 
a single instance may be here given, namely, 
that of the Mississippi, which is chosen because 
the amount of sediment brought down by this 
great river has been investigated with especial 
care by order of the United States Govern- 
ment The result is, as Mr. CroU shows, that 
the mean level of its enormous area of drainage 
must be lowered ^^7 of a foot annually, or 
I foot in 4566 years. Consequently, taking 
the best estimate of the mean height of the 
North American continent, viz. 748 feet, and 
looking to the future, the whole of the great 

• A. Tylor " On changes of the sea-level,* &c, * Philosophical 
Mag.* (Sen 4th) vol. v., 1853, p. 258. Archibald Geikie, Trans- 
actions Geolog. Soc. of Glasgow, vol. iii., p. 153 (read March, 
1868). Croll '*0n Geological Time," 'Philosophical Mag.,' 
May, August, and November, 1868. See also Croll, 'Climate 
and Time,' i87S» Chap. XX. For some recent information on 
the amount of sediment brought down by rivers, see ' Nature,' 
Sept. 23rd, 1880. Mr. T. Mellard Reade has published some 
interesting articles on the astonishing amount of matter brought 
down in solution by rivers. See Address, Geolog. Soc, Liver- 
pool, 1876-77. 



CHAP. V. AND DENUDATION.* 213 

Mississippi basin will be washed away, and 
'< brought down to the sea-level in less than 
''4,500,000 years, if no elevation of the land 
"takes place." Some rivers carry down much 
more sediment relatively to their size, and some 
much less than the Mississippi. 

Disintegrated matter is carried away by 
the wind as well as by running water. During 
volcanic outbursts much rock is triturated and 
is thus widely dispersed ; and in all arid 
countries the wind plays an important part 
in the removal of such matter. Wind-driven 
sand also wears down the hardest rocks. I 
have shown * that during four months of the 
year a large quantity of dust is blown from 
the north-western shores of Africa, and falls 
on the Atlantic over a space of 1600 miles 
in latitude, and for a distance of from 300 
to 600 miles from the coast. But dust has 
been seen to fall at a distance of 1030 miles 
from the shores of Africa. During a stay of 
three weeks at St Jago in the Cape Verde 
Archipelago, the atmosphere was almost always 
hazy, and extremely fine dust coming from 

* " An account of the fine dust which often falls on Vessels 
in the Atlantic Ocean,** Proc. Geolog. See. of London, June 
4th, 1845. 



2 1 4 DISINTEGRATION CHAP. V, 

Africa was continually falling. In some of 
this dust which fell in the open ocean at a 
distance of between 330 and 380 miles from 
the African coast, there were many particles 
of stone, about nAnr of an inch square. Nearer 
to the coast the water has been seen to be 
so much discoloured by the falling dust, that 
a sailing vessel left a track behind her. In 
countries, like the Cape Verde Archipelago, 
where it seldom rains and there are no frosts, 
the solid rock nevertheless disintegrates; and 
in conformity with the views lately advanced 
by a distinguished Belgian geologbt, De 
Koninck, such disintegration may be attributed 
in chief part to the action of the carbonic and 
nitric acids, together with the nitrates and 
nitrites of ammonia, dissolved in the dew. 

In all humid, even moderately humid, 
countries, worms aid in the work of denuda- 
tion in several ways. The vegetable mould 
which covers, as with a mantle, the surface of 
the land, has all passed many times through 
their bodies. Moidd differs in appearance 
from the subsoil only in its dark colour, and 
in the absence of fragments or particles of 
stone (when such are present in the subsoil), 
larger than those which can pass through the 



CHAP. V. AND DENUDATION. 215 

alimentary canal of a worm. This sifting of 
the soil is aided, ^ has already been remarked, 
by burrowing animals of many kinds, especially 
by ants. In countries where the summer is 
long and dry, the mould in protected places 
must be largely increased by dust blown from 
other and more exposed places. For instance, 
the quantity of dust sometimes blown over the 
plains of La Plata, where there are no solid 
rocks, is so great, that during the " gran seco,'* 
1827 to 1830, the appearance of the land, 
which is here unenclosed, was so completely 
changed that the inhabitants could not recog- 
nise the limits of their own estates, and endless 
lawsuits arose. Immense quantities of dust 
are likewise blown about in Egypt and in the 
south of France. In China, as Richthofen 
maintains, beds appearing like fine sediment, 
several hundred feet in thickness and extend- 
ing over an enormous area, owe their origin 
to dust blown from the high lands of central 
Asia.* In humid countries like Great Britain, 

* For La Plata, see my 'Journal of Researches,' during the 
voyage of the Beagle^ 1845, p. 133. ]£lie de Beaumont has 
given (' Lemons de G^log. pratique,' tom. 1. 184s, P- 1^3) ^^ 
excellent account of the enormous quantity of dust which is 
transported in some countries. I cannot but think that Mr. 
Proctor has somewhat exi^gerated (* Pleasant Ways in Science,' 
1879^ p. 379) the agency of dust in a humid country like Great 



2 1 6 DISINTEGRATION CHAP. v. 

as long as the land remains in its natural 
state clothed with vegetation, the mould in 
any one place can hardly be much increased 
by dust ; but in its present condition^ the fields 
near high roads, where there is much traffic, 
must receive a considerable amount of dust, 
and when fields are harrowed during dry and 
windy weather, clouds of dust may be seen 
to be blown away. But in all these cases 
the surface-soil is merely transported from one 
place to another. The dust which falls so 
thickly within our houses consists largely of 
organic matter, and if spread over the land 
would in time decay and disappear almost 
entirely. It appears, however, from recent 
observations on the snow-fields of the Arctic 
regions, that some little meteoric dust of extra 
mundane origin is continually falling. 

The dark colour of ordinary mould is 
obviously due to the presence of decaying 
organic matter, which, however, is present in 
but small quantities. The loss of weight 
which mould suffers when heated to redness 
seems to be in large part due to water in 

Britain. James Geikie has given C Prehistoric Europe,' 1880, 
p. 165) a full abstract of Richthofen's views, which, however, 
he disputes. 



CHAP.V. AND DENUDATION. 21 7 

combination being dispelled. In one sample 
of fertile mould the amount of organic matter 
was ascertained to be only 176 per cent; in 
some artificially prepared soil it was as much 
^5*5 P^i* cent, and in the famous black soil 
of Russia from 5 to even 12 per cent* In 
leaf-mould formed exclusively by the decay of 
leaves the amount is much greater, and in 
peat the carbon alone sometimes amounts to 
64 per cent ; but with these latter cases we 
are not here concerned. The carbon in the 
soil tends gradually to oxidise and to dis- 
appear, except where water accumulates and 
the climate is cool;t so that in the oldest 
pasture-land there is no great excess of organic 
matter, notwithstanding the continued decay 
of the roots and the underground stems of 
plants, and the occasional addition of manure. 
The disappearance of the organic matter from 
mould is probably much aided by its being 
brought again and again to the surface in the 
castings of worms. 

* These statements are taken from Hensen in ' Zeitschrift 
liir wissenschaft. Zoologie.' Bd. zxviiL, 1877, p. 36a Those 
with respect to peat are taken from Mr. A. A. Julien in ' Proc. 
American Assoc. Science,' 1879, P* 3i4- 

t I have given some &ct8 on the climate necessary or 
favourable for the formation of peat, in my 'Journal of 
Researches/ i845» p. 287. 



2 1 8 DISINTEGRATION CHAP. V. 

Worms, on the other hand, add largely to 
the organic matter in the soil by the astonish- 
ing number of half-decayed leaves which they 
draw into their burrows to a depth of 2 or 3 
inches. They do this chiefly for obtaining 
food| but partly for closing the mouths of their 
burrows and for lining the upper part The 
leaves which they consume are moistened, 
torn into small shreds, partially digested, and 
intimately commingled with earth ; and it is 
this process which gives to vegetable mould its 
uniform dark tint. It is known that various 
kinds of acids are generated by the decay of 
vegetable matter; and from the contents of 
the intestines of worms and from their castings 
being acid, it seems probable that the process 
of digestion induces an analogous chemical 
change in the swallowed, triturated, and half- 
decayed leaves. The large quantity of car- 
bonate of lime secreted by the calciferous 
glands apparently serves to neutralise the 
acids thus generated; for the digestive fluid 
of worms will not act unless it be alkaline. 
As the contents of the upper part of their 
intestines are acid, the acidity can hardly be 
due to the presence of uric acid. We may 
therefore conclude that the acids in the^ 



CHAP.V. AND DENUDATION. 219 

alimentary canal of worms are formed during the 
digestive process ; and that probably they are 
nearly of the same nature as those in ordinary 
mould or humus. The latter are well known 
to have the power of de-oxidising or dissolving 
per-oxide of iron, as may be seen wherever 
peat overlies red sand, or where a rotten root 
penetrates such sand. Now I kept some 
worms in a pot filled with very fine reddish 
sand, consisting of minute particles of silex 
coated with the red oxide of iron ; and the 
burrows, which the worms made through this 
sand, were lined or coated in the usual manner 
with their castings, formed of the sand mingled 
with their intestinal secretions and the refuse 
of the digested leaves; and this sand had 
almost wholly lost its red colour. When small 
portions of it were placed under the micro- 
scope, most of the grains were seen to be 
transparent and colourless, owing to the disso- 
lution of the oxide ; whilst almost all the grains 
taken from other parts of the pot were coated 
with the oxide. Acetic acid produced hardly 
any effect on his sand ; and even hydrochloric, 
nitric and sulphuric acids, diluted as in the 
Pharmacopoeia, produced less effect than did 
the acids in the intestines of the worms. 



220 DISINTEGRATION CHAP. V. 

Mr. A. A. JuHen has lately collected all the 
extant information about the acids generated 
in humus, which, according to some chemists, 
amount to more than a dozen different kinds. 
These acids, as well as their acid salts (i.e., in 
combination with potash, soda, and ammonia), 
act energetically on carbonate of lime and on 
the oxides of iron. It is also known that some 
of these acids, which were called long ago by 
Th^nard azohumic, are enabled to dissolve 
colloid silica in proportion to the nitrogen 
which they contain.* In the formation of 
these latter acids worms probably afford some 
aid, for Dr. H. Johnson informs me that by 
Nessler's test he found o'oiS per cent of 
ammonia in their castings. 

It may be here added that I have recently 
been informed by Dr. Gilbert '^that several 
'^ square yards on his lawn were swept clean, 
'* and after two or three weeks all the worm- 
''castings on the space were collected and 
" dried. These were found to contain 0*35 of 



* A. A. Julien '* On Uie Geological action of the Humus- 
acids," 'Proc American Assoc. Science,' voL xxviii., 1879, 
p. 311. Also on *' Chemical erosion on Mountain Summits ; " 
* New York Academy of Sciences,' Oct. 14, 1878, as quoted in 
the 'American Naturalist.' See also, on this subject, S. W. 
Johnson, * How Crops Feed,* 1870, p. 138. 



CHAP.V. AND DENUDATION. 221 

'* nitrogen. This is from two to three times 
'^as much as we find in our ordinary arable 
" surface-soil ; more than in our ordinary 
''pasture surface-soil; but less than in rich 
" kitchen-garden mould. Supposing a quantity 
'< of castings equal to lo tons in the dry state 
''were annually deposited on an acre, this 
"would represent a manuring of 78 lbs. of 
"nitrogen per acre per annum; and this is 
" very much more than the amount of nitrogen 
'' in the annual yield of hay per acre, if raised 
" without any nitrogenous manure. Obviously, 
"so far as the nitrogen in the castings is 
** derived from surface-growth or from surface- 
'' soil, it is not a gain to the latter; but so far 
"as it is derived from below, it is a gain.'' 

The several humus-acids, which appear, as 
we have just seen, to be generated within the 
bodies of worms during the digestive process, 
and their acid salts, play a highly important 
part, according to the recent observations of 
Mr. Julien, in the disintegration of various 
kinds of rocks. It has long been known that 
the carbonic acid, and no doubt nitric and 
nitrous acids, which are present in rain-water, 
act in like manner. There is, also, a great 
excess of carbonic acid in all soils, especially 



222 DISINTEGRATION CHAP. V. 

in rich soils, and this is dissolved by the water 
in the ground. The living roots of plants, 
moreover, as Sachs and others have shown, 
quickly corrode and leave their impressions 
on polbhed slabs of marble, dolomite and 
phosphate of lime. They will attack even 
basalt and sandstone.* But we are not here 
concerned with agencies which are wholly 
independent of the action of worms. 

The combination of any acid with a base 
is much facilitated by agitation, as fresh sur- 
faces are thus continually brought into contact. 
This will be thoroughly effected with the 
particles of stone and earth in the intestines 
of worms, during the digestive process ; and 
it should be remembered that the entire mass 
of the mould over every field, passes, in the 
course of a few years, through their alimentary 
canals. Moreover as the old burrows slowly 
collapse, and as fresh castings are continually 
brought to the surface, the whole superficial 
layer of mould slowly revolves or circulates ; 
and the friction of the particles one with 
another will rub off the finest films of dis- 
integrated matter as soon as they are formed. 

* See, for references on this subject, S. W<. Johnson, * How 
Crops Feed,' 1870, p. 326. 



CHAP. V. AND DENUDATION. 223 

Through these several means, minute fragments 
of rocks of many kinds and mere particles 
in the soil will be continually exposed to 
chemical decomposition ; and thus the amount 
of soil will tend to increase. 

As worms line their burrows with their 
castings, and as the burrows penetrate to a 
depth of 5 or 6, or even more feet, some small 
amount of the humus-adds will be carried 
far down, and will there act on the under- 
lying rocks and fragments of rock. Thus the 
thickness of the soil, if none be removed from 
the surface, will steadily though slowly tend 
to increase ; but the accumulation will after a 
time delay the disintegration of the underlying 
rocks and of the more deeply seated particles. 
For the humus-acids which are generated 
chiefly in the upper layer of vegetable mould, 
are extremely unstable compounds, and are 
liable to decomposition before they reach any 
considerable depth.* A thick bed of overlying 
soil will also check the downward extension 
of great fluctuations of temperature, and in 
cold countries will check the powerful action 
of frost The free access of air will likewise 

* This statement is taken from Mr. Julien, ' Proc. American 
Assoc. Science/ vol xxviii.^ 1879, P* 33^* 



224 DISINTEGRATION CHAP. V. 

be excluded. From these several causes dis- 
integration would be almost arrested, if the 
overlying mould were to increase much in 
thickness, owing to none or little being re- 
moved from the surface * In my own imme- 
diate neighbourhood we have a curious proof 
how effectually a few feet of clay checks some 
change which goes on in flints, lying freely 
exposed; for the large ones which have lain 
for some time on the surface of ploughed 
fields cannot be used for building; they will 
not cleave properly, and are said by the work- 
men to be rotten.f It is therefore necessary 
to obtain flints for building purposes from the 

* The preservative power of a layer of mould and turf is 
often shown by the perfect state of the glacial scratches on 
rocks when first uncovered. Mr. J. Geikie maintains, in his 
last very interesting work (' Prehistoric Europe,' 1881), that the 
more perfect scratches are probably due to the last access of 
cold and increase of ice, during the long-continued, inter- 
mittent glacial period. 

t Many geologists have felt much surprise at the complete 
disappearance of flints over wide and nearly level areas, from 
which the chalk has been removed by subaerial denudation. 
But the surface of every flint is coated by an opaque modified 
layer, which will just yield to a steel point, whilst the freshly 
fractured, translucent surface will not thus yield. The removal 
by atmospheric agencies of the outer modified surfaces of freely 
exposed flints, though no doubt excessively slow, together with 
the modification travelling inwards, will, as may be suspected, 
ultimately lead to their complete disintegration, notwithstanding 
that they appear to be so extremely durable. 



CHAP. V. AND DENUDATION. 225 

bed of red clay overlying the chalk (the residue 
of its dissolution by rain-water) or from the 
chalk itself. 

Not only do worms aid directly in the 
chemical disintegration of rocks, but there 
is good reason to believe that they likewise 
act in a direct and mechanical manner on 
the smaller particles. All the species which 
swallow earth are furnished with gizzards ; and 
these are lined with so thick a chitinous 
membrane, that Perrier speaks of it,* as " une 
veritable armature." The gizzard is sur- 
rounded by powerful transverse muscles, which, 
according to Clapar^de, are about ten times as 
thick as the longitudinal ones; and Perrier 
saw them contracting energetically. Worms 
belonging to one genus, Digaster, have two 
distinct but quite similar gizzards; and in 
another genus, Moniligaster, the second gizzard 
consists of four pouches, one succeeding the 
other, so that it may almost be said to have 
five gizzards.! In the same manner as gallina- 
ceous and struthious birds swallow stones to aid 
in the trituration of their food, so it appears 

* 'Archives de Zoolog. exp^.* torn. iii. 1874, p. 409. 
t 'Nottvelles Archives du Museum,' torn. viii. 1872, pp. 95, 
131. 

Q 



2 26 DISINTEGRATION CHAP. V. 

to be with terricolous worms. The gizzards of 
thirty-eight of our common worms were opened, 
and in twenty-five of them small stones or 
grains of sand, sometimes together with the 
hard calcareous concretions formed within the 
anterior calciferous glands, were found, and in 
two others concretions alone. In the gizzards 
of the remaining worms there were no stones ; 
but some of these were not real exceptions, as 
the gizzards were opened late in the autumn, 
when the worms had ceased to feed and their 
gizzards were quite empty.* 

When worms make their burrows through 
earth abounding with little stones, no doubt 
many will be unavoidably swallowed; but it 
must not be supposed that this fact accounts 
for the frequency with which stones and sand 
are found in their gizzards. For beads of 
glass and fragments of brick and of hard tiles 
were scattered over the surface of the earth, 
in pots in which worms were kept and had 
already made their burrows; and very many 
of these beads and fragments were picked up 
and swallowed by the worms, for they were 



* Morren, in speaking of the earth in the alimentary canals 
of worms, says, " praesep^ cum lapillis commixtam vidi :* ' De 
Lumbrici terrestris Hist. Nat.' &c., 1829, p. 16. 



CHAP.V. AND DENUDATION. 227 

found in their castings, intestines, and gizzards. 
They even swallowed the coarse red dust, 
formed by the pounding of the tiles. Nor can 
it be supposed that they mistook the beads 
and fragments for food ; for we have seen that 
their taste is delicate enough to distinguish 
between different kinds of leaves. It is there- 
fore manifest that they swallow hard objects, 
such as bits of stone, beads of glass and 
angular fragments of bricks or tiles for some 
special purpose ; and it can hardly be doubted 
that this is to aid their gizzards in crushing 
and grinding the earth, which they so largely 
consume. That such hard objects are not 
necessary for crushing leaves, may be inferred 
from the &ct that certain species, which live 
in mud or water and feed on dead or living 
vegetable matter, but which do not swallow 
earth, are not provided with gizzards,* and 
therefore cannot have the power of utilising 
stones. 

During the grinding process, the particles 
of earth must be rubbed against one another, 
and between the stones and the tough lining 
membrane of the gizzard. The softer particles 
will thus sufifer some attrition, and will perhaps 

* Perrier, 'Archives de Zool<^. expdr.' torn. HL 1874, p. 419. 



228 DISINTEGRATION CHAP. v. 

even be crushed. This conclusion is supported 
by the appearance of freshly ejected castings, 
for these often reminded me of the appearance 
of paint which has just been ground by a 
workman between two flat stones. Morren 
remarks that the intestinal canal is ''impleta 
tenuissimi terri, veluti in pulverem redact^." * 
Perrier also speaks of 'M'^tat de pdte exces- 
sivement fine h, laquelle est r^duite la terre 
qu'ils rejettent," &c.t 

As the amount of trituration which the 
particles of earth undergo in the gizzards of 
worms possesses some interest (as we shall 
hereafter see), I endeavoured to obtain evi- 
dence on this head by carefully examining 
many of the fragments which had passed 
through their alimentary canals. With worms 
living in a state of nature, it is of course 
impossible to know how much the fragments 
may have been worn before they were 
swallowed. It is, however, clear that worms 
do not habitually select already rounded par- 
ticles, for sharply angular bits of flint and of 
other hard rocks were often found in their 
gizzards or intestines. On three occasions 

♦ Morren, * Dc Lumbrici terrestris Hist. Nat.' &c., p. 16. 
t * Archives de Zoolog. exp^r.' torn. iii. 1874, P* 418. 



CHAP. V. AND DENUDATION. 229 

sharp spines from the stems of rose-bushes 
were thus found. Worms kept in confinement 
repeatedly swallowed angular fragments of 
hard tile, coal, cinders^ and even the sharpest 
fragments of glass. Gallinaceous and stru- 
thious birds retain the same stones in their 
gizzards for a long time, which thus become 
well rounded ; but this does not appear to be 
the case with worms, judging from the large 
number of the fragments of tiles, glass beads, 
stones, &c, commonly found in their castings 
and intestines. So that unless the same 
fragments were to pass repeatedly through 
their gizzards, visible signs of attrition in the 
fragments could hardly be expected, except 
perhaps in the case of very soft stones. 

I will now give such evidence of attrition 
as I have been able to collect. In the gizzards 
of some worms dug out of a thin bed of mould 
over the chalk, there were many well-rounded 
small fragments of chalk, and two fragments 
of the shells of a land-mollusc (as ascertained 
by their microscopical structure), which latter 
were not only rounded but somewhat polished. 
The calcareous concretions formed in the 
calciferous glands, which are often found in 
their gizzards, intestines, and occasionally in 



230 DISINTEGRATION CHAP. V. 

their castings, when of lai^ size, sometimes 
appeared to have been rounded ; but with all 
calcareous bodies the rounded appearance may 
be partly or wholly due to their corrosion by 
carbonic acid and the humus-acids. In the 
gizzards of several worms collected in my 
kitchen garden near a hothouse, eight little 
fragments of cinders were found, and of these, 
six appeared more or less rounded, as were 
two bits of brick; but some other bits were 
not at all rounded. A farm-road near Abinger 
Hall had been covered seven years before 
with brick-rubbish to the depth of about 
6 inches ; turf had grown over this rubbish on 
both sides of the road for a width of 18 inches, 
and on this turf there were innumerable cast- 
ings. Some of them were coloured of a 
uniform red owing to the presence of much 
brick-dust, and they contained many particles 
of brick and of hard mortar from i to 3 mm. 
in diameter, most of which were plainly 
rounded; but all these particles may have 
been rounded before they were protected by 
the turf and were swallowed, like those on the 
bare parts of the road which were much worn. 
A hole in a pasture-field had been filled up 
with brick-rubbish at the same time, viz., seven 



CHAP. V. AND DENUDATION. 23 1 

years ago, and was now covered with turf; 
and here the castings contained very many 
particles of brick, all more or less rounded; 
and this brick-rubbish, after being shot into 
the hole, could not have undergone any 
attrition. Again, old bricks very little broken, 
together with fragments of mortar, were laid 
down to form walks, and were then covered 
with from 4 to 6 inches of gravel ; six little 
fragments of brick were extracted from castings 
collected on these walks, three of which were 
plainly worn. There were also very many 
particles of hard mortar, about half of which 
were well rounded ; and it is not credible that 
these could have suffered so much corrosion 
from the action of carbonic acid in the course 
of only seven years. 

Much better evidence of the attrition of 
hard objects in the gizzards of worms, is 
afforded by the state of the small fragments 
of tiles or bricks, and of concrete in the castings 
thrown up where ancient buildings once stood. 
As all the mould covering a field passes every 
few years through the bodies of worms, the 
same small fragments will probably be swal- 
lowed and brought to the surface many times 
in the course of centuries. It should be 



232 DISINTEGRATION CHAP. V. 

premised that in the several following cases» 
the finer matter was first washed away firom the 
castings, and then all the particles of bricks, 
tiles and concrete were collected without any 
selection, and were afterwards examined. Now 
in the castings ejected between the tesserae on 
one of the buried floors of the Roman villa at 
Abinger, there were many particles (from ^ to 
2 mm. in diameter) of tiles and concrete, which 
it was impossible to look at with the naked 
eye or through a strong lens, and doubt for a 
moment that they had almost all undergone 
much attrition. I speak thus after having 
examined small water-worn pebbles, formed 
from Roman bricks, which M. Henri de 
Saussure had the kindness to send me, and 
which he had extracted from sand and gravel 
beds, deposited on the shores of the Lake of 
Geneva, at a former period when the water 
stood at about two metres above its present 
level. The smallest of these water-worn 
pebbles of brick from Geneva resembled 
closely many of those extracted from the 
gizzards of worms, but the larger ones were 
somewhat smoother. 

Four castings found on the recently un- 
covered, tesselated floor of the great room in 



CHAP. V. AND DENUDATION. 233 

the Roman villa at Brading, contained many 
particles of tile or brick, of mortar, and of 
hard white cement ; and the majority of these 
appeared plainly worn. The particles of 
mortar, however, seemed to have suffered 
more corrosion than attrition, for grains of 
silex often projected from their surfaces. 
Castings from within the nave of Beaulieu 
Abbey, which was destroyed by Henry VIII., 
were collected from a level expanse of turf, 
overlying the buried tesselated pavement, 
through which worm-burrows passed ; and 
these castings contained innumerable particles 
of tiles and bricks, of concrete and cement, 
the majority of which had manifestly under- 
gone some or much attrition. There were 
also many minute flakes of a micaceous slate, 
the points of which were rounded. If the 
above supposition, that in all these cases the 
same minute fragments have passed several 
times through the gizzards of worms, be re- 
jected, notwithstanding its inherent probability, 
we must then assume that in all the above 
cases the many rounded fragments found in 
the castings had all accidentally undergone 
much attrition before they were swallowed ; 
and this is highly improbable. 



234 DISINTEGRATION CHAP. V, 

On the other hand it must be stated that 
fragments of ornamental tiles, somewhat harder 
than common tiles or bricks, which had been 
swallowed only once by worms kept in con- 
finement, were with the doubtful exception of 
one or two of the smallest grains, not at all 
rounded. Nevertheless some of them ap- 
peared a little worn, though not rounded. 
Notwithstanding these cases, if we consider 
the evidence above given, there can be little 
doubt that the fragments, which serve as mill- 
stones in the gizzards of worms, suffer, when 
of a not very hard texture, some amount of 
attrition ; and that the smaller particles in the 
earth, which is habitually swallowed in such 
astonishingly large quantities by worms, are 
ground together and are thus levigated. If 
this be the case, the "terra tenuissima," — 
the " p4te excessivement fine,"— of which the 
castings largely consist, is in part due to the 
mechanical action of the gizzard;* and this 

* This condttsion reminds me of the vast amount of 
extremely fine chalky mud which is found within the lagoons 
of many atolls, where the sea is tranquil and waves cannot 
triturate the blocks of coraL This mud must, as I believe 
('The Structure and Distribution of Coral-Reefs,' 2nd edit. 
1874, p. 19), be attributed to the innumerable annelids and 
other animals which burrow into the dead coral, and to the 
fishes, Holothurians, &c., which browse on the living corals. 



CHAP. V. AND DENUDATION. 235 

fine matter, as we shall see in the next chapter, 
is that which is chiefly washed away from the 
innumerable castings on every field during 
each heavy shower of rain. If the softer 
stones yield at all, the harder ones will suffer 
some slight amount of wear and tear. 

The trituration of small particles of stone 
in the gizzards of worms is of more import- 
ance under a geological point of view than 
may at first appear to be the case; for Mr. 
Sorby has clearly shown that the ordinary 
means of disintegration, namely, running water 
and the waves of the sea, act with less and 
less power on fragments of rock the smaller 
they are. "Hence,** as he remarks, "even 
"making no allowance for the extra buoying 
" up of very minute particles by a current of 
''water, depending on surface cohesion, the 
'* effects of wearing on the form of the grains 
"must vary directly as their diameter or there- 
"abouts. If so, a grain ^ of an inch in 
'^ diameter would be worn ten times as much 
''as one xkr of an inch in diameter, and at 
"least a hundred times as much as one yoW 
"of an inch in diameter. Perhaps, then, we 
" may conclude that a grain iV of an inch in 
"diameter would be worn as much or more 



236 DISINTEGRATION AND DENUDATION. CHAP. V. 

" in drifting a mile as a grain tiArf of an inch 
''in being drifted 100 miles. On the same 
** principle a pebble one inch in diameter would 
"be worn relatively more by being drifted only 
"a few hundred yards.'** Nor should we 
forget, in considering the power which worms 
exert in triturating particles of rock, that there 
is good evidence that on each acre of land, 
which is sufficiently damp and not too sandy, 
gravelly or rocky for worms to inhabit, a 
weight of more than ten tons of earth annually 
passes through their bodies and is brought to 
the surface. The result for a country of the 
size of Great Britain, within a period not very 
long in a geolc^cal sense, such as a million 
years, cannot be insignificant ; for the ten tons 
of earth has to be multiplied first by the above 
number of years, and then by the number 
of acres fully stocked with worms; and in 
England, together with Scotland, the land 
which is cultivated and is well fitted for these 
animals, has been estimated at above 32 
million acres. The product is 320 million 
million tons of earth. 

♦ Anniversary Address: *The Quarterly Journal of the 
Geological Soc.' May 1880, p. 59. 



( 237 ) 



CHAPTER VI. 

THE DENUDATION OF THE LAND — COnHnUid. 

Denudation aided by recently ejected castings flowing down 
inclined grass-covered surfaces — ^The amount of earth which 
annually flows downwards—The effect of tropical rain on 
worm castings — ^The finest particles of earth washed com- 
pletely away from castings— -The disintegration of dried 
castings into pellets, and their rolling down inclined sur- 
faces — ^The formation of little ledges on hill-sides, in part 
due to the accumulation of disintegrated castings — Castings 
blown to leeward over level land— An attempt to estimate 
the amount thus blown— The degradation of ancient en- 
campments and tumuli — The preservation of the crowns 
and furrows on land anciently ploughed — The formation 
and amount of mould over the Chalk formation. 

Wb are now prepared to consider the more 
direct part which worms take in the denudation 
of the land. When reflecting on sub-aerial 
denudation, it formerly appeared to me, as it 
has to others, that a nearly level or very gently 
inclined surface, covered with turf, could suffer 
no loss during even a long lapse of time. It 
may, however, be urged that at long intervals, 
debacles of rain or water-spouts would remove 
all the mould from a very gentle slope; but 



238 DENUDATION OF THE LAND CHAP. VI. 

when examining the steep, turf-covered slopes 
in Glen Roy, I was struck with the fact how 
rarely any such event could have happened 
since the Glacial period, as was plain from the 
well-preserved state of the three successive 
''roads'' or lake-mai^ins. But the difficulty 
in believing that earth in any appreciable 
quantity can be removed from a gently in- 
clined surface, covered with vegetation and 
matted with roots, is removed through the 
agency of worms. For the many castings 
which are thrown up during rain, and those 
thrown up some little time before heavy rain, 
flow for a short distance down an inclined 
surface. Moreover much of the finest levi- 
gated earth is washed completely away from 
the castings. During dry weather castings 
often disintegrate into small rounded pellets, 
and these from their weight often roll down 
any slope. This is more especially apt to 
occur when they are started by the wind, 
and probably when started by the touch of an 
animal, however small. We shall also see 
that a strong wind blows all the castings, 
even on a level field, to leeward, whilst they 
are soft ; and in like manner the pellets when 
they are dry. If the wind blows in nearly 



CHAP. VI. AIDED BY WORMS. 239 

the direction of an inclined surface, the flowing 
down of the castings is much aided. 

The observations on which these several 
statements are founded must now be given in 
some detail. Castings when first ejected are 
viscid and soft; during rain, at which time 
worms apparently prefer to eject them, they 
are still softer; so that I have sometimes 
thought that worms must swallow much water 
at such times. However this may be, rain, 
even when not very heavy, if long continued, 
renders recently-ejected castings semi-fluid; 
and on level ground they then spread out into 
thin, circular, flat discs, exactly as would so 
much honey or very soft mortar, with all traces 
of their vermiform structure lost. This latter 
fact was sometimes made evident, when a 
worm had subsequently bored through a flat 
circular disc of this kind, and heaped up a 
fresh vermiform mass in the centre. These 
flat subsided discs have been repeatedly seen 
by me after heavy rain, in many places on 
land of all kinds. 

On the flowing of wet castings, and the 
rolling of dry disintegrated castings down 
inclined surfaces. — ^When castings are ejected 
on an inclined surface during or shortly before 



240 DENUDATION OF THE LAND CHAP. VI, 

heavy rain, they cannot fail to flow a little 
down the slope. Thus, on some steep slopes 
in Knole Park, which were covered with coarse 
grass and had apparently existed in this state 
from time immemorial, I found (Oct. 22, 1872) 
after several wet days that almost all the many 
castings were considerably elongated in the 
line of the slope ; and that they now consisted 
of smooth, only slightly conical masses. When- 
ever the mouths of the burrows could be found 
from which the earth had been ejected, there 
was more earth below than above them. After 
some heavy storms of rain (Jan. 25, 1872) two 
rather steeply inclined fields near Down, which 
had formerly been ploughed and were now 
rather sparsely clothed with poor grass, were 
visited, and many castings extended down the 
slopes for a length of 5 inches, which was twice 
or thrice the usual diameter of the castings 
thrown up on the level parts of these same 
fields. On some fine grassy slopes in Holwood 
Park, inclined at angles between 8° and 1 1° 30' 
with the horizon, where the surface apparently 
had never been disturbed by the hand of man, 
castings abounded in extraordinary numbers: 
and a space 16 inches in length transversely 
to the slope and 6 inches in the line of the 



CHAP. VI. AIDED BY WORMS. 24 1 

slope, was completely coated, between the 
blades of grass, with a uniform sheet of con- 
fluent and subsided castings. Here also in 
many places the castings had flowed down the 
slope, and now formed smooth narrow patches 
of earth, 6, 7, and 7^ inches in length. Some 
of these consisted of two castings, one above 
the other, which had become so completely 
confluent that they could hardly be distin- 
guished. On my lawn, clothed with very 
fine grass, most of the castings are black, but 
some are yellowish from earth having been 
brought up from a greater depth than usual, 
and the flowing-down of these yellow castings 
after heavy rain, could be clearly seen where 
the slope was 5^ ; and where it was less than 
i^ some evidence of their flowing down could 
still be detected. On another occasion, after 
rain which was never heavy, but which lasted 
for 18 hours, all the castings on this same 
gently inclined lawn had lost their vermiform 
structure ; and they had flowed, so that fully 
two-thirds of the ejected earth lay below the 
mouths of the burrows. 

These observations led me to make others 
with more care. Eight castings were found 
on my lawn, where the grass-blades are fine and 

R 



242 DENUDATION OF THE LAND CHAP. VU 

close together, and three others on a field with 
coarse grass. The inclination of the surface at 
the eleven places where these castings were 
collected varied between 4^ 30' and 17^ 30'; 
the mean of the eleven inclinations being 
9° 26'. The length of the castings in the 
direction of the slope was first measured with 
as much accuracy as their irregularities would 
permit It was found possible to make these 
measurements within about i of an inch, but 
one of the castings was too irregular to admit 
of measurement. The average length in the 
direction of the slope of the remaining ten 
castings was 2*03 inches. The castings were 
then divided with a knife into two parts along 
a horizontal line passing through the mouth 
of the burrow, which was discovered by slicing 
off the turf; and all the ejected earth was 
separately collected, namely, the part above 
the hole and the part below. Afterwards 
these two parts were weighed. In every case 
there was much more earth below than above ; 
the mean weight of that above being 103 
grains, and of that below 205 grains ; so that 
the latter was very nearly double the former. 
As on level ground castings are commonly 
thrown up almost equally round the mouths 



CHAP. VI. AIDED BY WORMS. 243 

of the burrows, this difference in weight in- 
dicates the amount of ejected earth which 
had flowed down the slope. But very many 
more observations would be requisite to arrive 
at any general result ; for the nature of the 
vegetation and other accidental circumstances, 
such as the heaviness of the rain, the direction 
and force of the wind, &c., appear to be more 
important in determining the quantity of the 
earth which flows down a slope than its angle. 
Thus with four castings on my lawn (included 
in the above eleven) where the mean slope 
was 7^ 19', the diflerence in the amount of 
earth above and below the burrows was 
greater than with three other castings on the 
same lawn where the mean slope was 12° 5'. 

We may, however, take the above eleven 
cases, which are accurate as far as they go, and 
calculate the weight of the ejected earth which 
annually flows down a slope having a mean 
inclination of 9® 26'. This was done by my 
son George. It has been shown that almost 
exactly two-thirds of the ejected earth is found 
below the mouth of the burrow and one-third 
above it. Now if the two-thirds which is 
below the hole be divided into two equal 
parts, the upper half of this two-thirds exactly 



244 DENUDATION OF THE LAND CHAP. VI. 

counterbalances the one-third which is above 
the hole, so that as far as regards the one- 
third above and the upper half of the two- 
thirds below, there is no flow of earth down the 
hill-side. The earth constituting the lower half 
of the two-thirds b, however, displaced through 
distances which are different for every part 
of it, but which may be represented by the 
distance between the middle point of the lower 
half of the two-thirds and the hole. So that 
the average distance of displacement is a half 
of the whole length of the worm-casting. 
Now the average length of ten out of the 
above eleven castings was 2*03 inches, and 
half of this we may take as being i inch. It 
may therefore be concluded that one-third of 
the whole earth brought to the siu-face was in 
these cases carried down the slope through 
I inch.* 

It was shown in the third chapter that on 
Leith Hill Common, dry earth weighing at 
least 7*453 lbs. was brought up by worms to 
the surface on a square yard in the course of 

* Mr. James Wallace has pointed out that it is necessary 
to take into consideration the possibility of barrows being 
made at right angles to the surface instead of vertically down, 
in which case the lateral displacement of the soil would be 
increased. 



CHAP. VI. AIDED BY WORMS. 245 

a yean If a square jrard be drawn on a hill- 
side with two of its sides horizontal, then it is 
clear that only ^ part of the earth brought up 
on that square jrard would be near enough to 
its lower side to cross it, supposing the dis- 
placement of the earth to be through one inch. 
But it appears that only i of the earth brought 
up can be considered to flow downwards ; 
hence i of ^ or ^ of 7*453 lbs. will cross the 
lower side of our square yard in a year. Now 
yjffof 7*453 lbs. is I'l oz. Therefore I'l oz. 
of dry earth will annually cross each linear 
yard running horizontally along a slope having 
the above inclination; or very nearly 7 lbs. 
will annually cross a horizontal line, 100 yards 
in length, on a hill-side liaving this inclination. 
A more accurate, though still very rough, 
calculation can be made of the bulk of earth, 
which in its natural damp state annually flows 
down the same slope over a yard-line drawn 
horizontally across it. From the several cases 
given in the third chapter, it is known that the 
castings annually brought to the surface on a 
square yard, if uniformly spread out would 
form a layer '2 of an inch in thickness: it 
therefore follows by a calculation similar to the 
one already given, that i of -2 x 36, or 2*4 



246 DENUDATION OF THE LAND CHAP. VT. 

cubic inches of damp earth will annually cross 
a horizontal line one yard in length on a hill- 
side with the above inclination. This bulk of 
damp castings was found to weigh 1*85 oz. 
Therefore 1 1 '56 lbs. of damp earth, instead of 
7 lbs. of dry earth as by the former calculation, 
would annually cross a line 100 yards in length 
on our inclined surface. 

In these calculations it has been assumed 
that the castings flow a short distance down- 
wards during the whole year, but this occurs 
only with those ejected during or shortly before 
rain; so that the above results are thus far 
exaggerated. On the other hand, during rain 
much of the finest earth is washed to a con- 
siderable distance from the castings, even 
where the slope is an extremely gentle one, 
and is thus wholly lost as far as the above 
calculations are concerned. Castings ejected 
during dry weather and which have set hard, 
lose in the same manner a considerable quantity 
of fine earth. Dried castings, moreover, are 
apt to disintegrate into little pellets, which 
often roll or are blown down any inclined 
surface. Therefore the above result, namely, 
that 2*4 cubic inches of earth (weighing i '85 oz. 
whilst damp) annually crosses a yard-line of 



CHAP. VI. AIDED BV WORMS. 247 

the Specified kind, is probably not much if at 
all exaggerated. 

This amount is small ; but we should bear 
in mind how many branching valleys intersect 
most countries, the whole length of which 
must be very great ; and that earth is steadily 
travelling down both turf-covered sides of 
each valley. For every loo yards in length 
in a valley with sides sloping as in the fore- 
going cases, 480 cubic inches of damp earth, 
weighing above 23 pounds, will annually reach 
the bottom. Here a thick bed of alluvium 
will accumulate, ready to be washed away in 
the course of centuries, as the stream in the 
middle meanders from side to side. 

If it could be shown that worms generally 
excavate their burrows at right angles to an 
inclined surface, and this would be their 
shortest course for bringing up earth from 
beneath, then as the old burrows collapsed 
from the weight of the superincumbent soil, 
the collapsing would inevitably cause the whole 
bed of vegetable mould to sink or slide slowly 
down the inclined surface. But to ascertain 
the direction of many burrows was found too 
difficult and troublesome. A straight piece 
of wire was, however, pushed into twenty-five 



248 DENUDATION OF THE LAND CHAP, VI. 

burrows on several sloping fields, and in eight 
cases the burrows were nearly at right angles 
to the slope; whilst in the remaining cases 
they were indifferently directed at various 
angles, either upwards or downwards with 
respect to the slope. 

In countries where the rain is very heavy, 
as in the tropics, the castings appear, as might 
have been expected, to be washed down in 
a greater degree than in England. Mr. Scott 
informs me that near Calcutta the tall columnar 
castings (previously described), the diameter 
of which is usually between i and i^ inch, 
subside on a level surface, after heavy rain, 
into almost circular, thin, flat discs, between 
3 and 4 and sometimes 5 inches in diameter. 
Three fresh castings, which had been ejected 
in the Botanic Gardens " on a slightly inclined, 
"grass-covered, artificial bank of loamy clay," 
were carefully measured, and had a mean 
height of 2*17, and a mean diameter of 1*43 
inches; these after heavy rain, formed elon- 
gated patches of earth, with a mean length 
in the direction of the slope of 5-83 inches. 
As the earth had spread very little up the 
slope, a large part, judging from the original 
diameter of these castings, must have flowed 



CHAP. VI. AIDED BY WORMS. 249 

bodily downwards about 4 inches. Moreover 
some of the finest earth of which they were 
composed must have been washed completely 
away to a still greater distance. In drier sites 
near Calcutta, a species of worm ejects its 
castings, not in vermiform masses, but in 
little pellets of varying sizes : these are very 
numerous in some places, and Mr. Scott says 
that they " are washed away by every shower." 
I was led to believe that a considerable 
quantity of fine earth is washed quite away 
from castings during rain, from the surfaces 
of old ones being often studded with coarse 
particles. Accordingly a little fine precipitated 
chalk, moistened with saliva or gum-water, so 
as to be slightly viscid and of the same con- 
sistence as a fresh casting, was placed on the 
summits of several castings and gently mixed 
with them. These castings were then watered 
through a very fine rose, the drops from which 
were closer together than those of rain, but 
not nearly so large as those in a thunder- 
storm; nor did they strike the ground with 
nearly so much force as drops during heavy 
rain. A casting thus treated subsided with 
surprising slowness, owing as I suppose to 
its viscidity. It did not flow bodily down 



250 DENUDATION OF THE LAND CHAP. VI. 

the grass-covered surface of the lawn, which 
was here inclined at an angle of 16'' 20'; 
nevertheless many particles of the chalk were 
found three inches below the casting. The 
experiment was repeated on three other cast- 
ings on different parts of the ^wn, which 
sloped at 2** 30', 3*" and 6**; and particles of 
chalk could be seen between 4 and 5 inches 
below the casting; and after the surface had 
become dry, particles were found in two cases 
at a distance of 5 and 6 inches. Several 
other castings with precipitated chalk placed 
on their summits were left to the natural 
action of the rain. In one case, after rain 
which was not heavy, the casting was longi- 
tudinally streaked with white. In two other 
cases the surface of the ground was rendered 
somewhat white for a distance of one inch 
from the casting; and some soil collected at 
a distance of 2^ inches, where the slope was 
7^, effervesced slightly when placed in acid. 
After one or two weeks, the chalk was wholly 
or almost wholly washed away from all the 
castings on which it had been placed, and 
these had recovered their natural colour. 

It may be here remarked that after very 
heavy rain shallow pools may be seen on level 



CHAP. VI. AIDED BY WORMS. 251 

or nearly level fields, where the soil is not 
very porous, and the water in them is often 
slightly muddy; when such little pools have 
dried, the leaves and blades of grass at their 
bottoms are generally coated with a thin layer 
of mud. This mud I believe is derived in 
large part from recently ejected castings. 

Dr. King informs me that the 'majority of 
the before described gigantic castings, which 
he found on a fully exposed, bare, gravelly 
knoll on the Nilgiri Mountains in India, had 
been more or less weathered by the previous 
north-east monsoon; and most of them pre- 
sented a subsided appearance. The worms 
here eject their castings only during the rainy 
season ; and at the time of Dr. King's visit no 
rain had fallen for no days. He carefully 
examined the ground between the place where 
these huge castings lay, and a little water- 
course at the base of the knoll, and nowhere 
was there any accumulation of fine earth, such 
as would necessarily have been left by the 
disintegration of the castings if they had not 
been wholly removed. He therefore has no 
hesitation in asserting that the whole of these 
huge castings are annually washed during the 
two monsoons (when about lOO inches of rain 



252 DENUDATION OF THE LAND CHAP. VI. 

fall) into the little water-course, and thence 
into the plains lying below at a depth of 3000 
or 4000 feet. 

Castings ejected before or during dry 
weather become hard^ sometimes surprisingly 
hardy from the particles of earth having been 
cemented together by the intestinal secretions. 
Frost seems to be less effective in their dis- 
integration than might have been expected. 
Nevertheless they readily disintegrate into 
small pellets^ after being alternately moistened 
with rain and again dried Those which have 
flowed during rain down a slope, disintegrate 
in the same manner. Such pellets often roll 
a little down any sloping surface ; their descent 
being sometimes much aided by the wind. 
The whole bottom of a broad dry ditch in 
my grounds, where there were very few fresh 
castings, was completely covered with these 
pellets or disintegrated castings, which had 
rolled down the steep sides, inclined at an 
angle of 27^. 

Near Nice, in places where the great cylin- 
drical castings^ previously described, abound, 
the soil consists of very fine arenaceo-cal- 
careous loam ; and Dr. King informs me that 
these castings are extremely liable to crumble 



CHAP. VI. AIDED BY WORMS. 253 

during dry weather into small fragments, 
which are soon acted on by rain, and then 
sink down so as to be no longer distinguishable 
from the surrounding soil. He sent me a mass 
of such disintegrated castings, collected on the 
top of a bank, where none could have rolled 
down from above. They must have been 
ejected within the previous five or six months, 
but they now consisted of more or less rounded 
fragments of all sizes, from | of an inch in 
diameter to minute grains and mere dust. Dr. 
King witnessed the crumbling process whilst 
drying some perfect castings, which he after- 
wards sent me. Mr. Scott also remarks on 
the crumbling of the castings near Calcutta 
and on the mountains of Sikkim during the 
hot and dry season. 

When the castings near Nice had been 
ejected on an inclined surface, the disintegrated 
fragments rolled downwards, without losing 
their distinctive shape; and in some places 
could "be collected in basketfuls." Dr. King 
observed a striking instance of this fact on the 
Corniche road, where a drain, about 2^ feet 
wide and 9 inches deep, had been made to 
catch the surface drainage from the adjoining 
hill-side. The bottom of this drain was covered 



254 DENUDATION OF THE LAND CHAP. VI. 

for a distance of several hundred yards, to a 
depth of from i^ to 3 inches, by a layer of 
broken castings, still retaining their character- 
istic shape. Nearly all these innumerable 
fragments had rolled down from above, for 
extremely few castings had been ejected in the 
drain itself. The hill-side was steep, but varied 
much in inclination, which Dr. King estimated 
at from 30^ to 60^ with the horizon. He 
climbed up the slope, and " found every here 
"and there little embankments, formed by 
'^fragments of the castings that had been 
"arrested in their downward progress by 
** irregularities of the surface, by stones, twigs, 
" &c. One little group of plants of Anemone 
^'hortensis had acted in this manner, and quite 
''a small bank of soil had collected round it 
" Much of this soil had crumbled down, but a 
"great deal of it still retained the form of 
'^ castings/' Dr. King dug up this plant, and 
was struck with the thickness of the soil which 
must have recently accumulated over the crown 
of the rhizoma, as shown by the length of the 
bleached petioles, in comparison with those of 
other plants of the same kind, where there had 
been no such accumulation. The earth thus 
accumulated had no doubt been secured (as I 



CHAP. VI. AIDED BY WORMS. 255 

have everywhere seen) by the smaller roots of 
the plants. After describing this and other 
analogous cases, Dr. King concludes: ''I can 
'* have no doubt that worms help greatly in the 
" process of denudation." 

Ledges of earth an steep kill-sides. — Little 
horizontal ledges, one above another, have 
been observed on steep grassy slopes in many 
parts of the world. The formation has been 
attributed to animals travelling repeatedly 
along the slope in the same horizontal lines 
while grazing, and that they do thus move and 
use the ledges is certain ; but Professor Hens- 
low (a most careful observer) told Sir J. Hooker 
that he was convinced that this was not the 
sole cause of their formation. Sir J. Hooker 
saw such ledges on the Himalayan and Atlas 
ranges, where there were no domesticated 
animals and not many wild ones; but these 
latter would, it is probable, use the ledges at 
night while grazing like our domesticated 
animals. A friend observed for me the ledges 
on the Alps of Switzerland, and states that 
they ran at 3 or 4 ft one above the other, and 
were about a foot in breadth. They had been 
deeply pitted by the feet of grazing cows. 
Similar ledges were observed by the same 



256 DENUDATION OF THE LAND. CHAP. VI. 

friend on our Chalk downs, and on an old 
talus of chalk-fragments (thrown out of a 
quarry) which had become clothed with turf. 

My son Francis examined a Chalk escarp- 
ment near Lewes ; and here on a part which 
was very steep, sloping at 40^ with the horizon, 
about 30 flat ledges extended horizontally for 
more than 100 yards, at an average distance 
of about 20 inches, one beneath the other. 
They were from 9 to 10 inches in breadth. 
When viewed from a distance they presented 
a striking appearance, owing to their parallelism ; 
but when examined closely, they were seen to 
be somewhat sinuous, and one often ran into 
another, giving the appearance of the ledge 
having forked into two. They are formed of 
light-coloured earth, which on the outside, 
where thickest, was in one case 9 inches, and 
in another case between 6 and 7 inches in 
thickness. Above the ledges, the thickness 
of the earth over the chalk was in the former 
case 4 and in the latter only 3 inches. The 
grass grew more vigorously on the outer edges 
of the ledges than on any other part of the 
slope, and here formed a tufted fringe. Their 
middle part was bare, but whether this had 
been caused by the trampling of sheep, which 



CHAP. VI. LEDGES ON HILL-SIDES. 257 

sometimes frequent the ledges, my son could 
not ascertain. Nor could he feel sure how 
much of the earth on the middle and bare 
parts, consisted of disintegrated worm-castings 
which had rolled down from above; but he 
felt convinced that some had thus originated ; 
and it was manifest that the ledges with their 
grass-fringed edges would arrest any small 
object rolling down from above. 

At one end or side of the bank bearing 
these ledges, the surface consisted in parts of 
bare chalk, and here the ledges were very 
irregular. At the other end of the bank, the 
slope suddenly became less steep, and here the 
ledges ceased rather abruptly; but little em- 
bankments only a foot or two in length were 
still present. The slope became steeper lower 
down the hill, and the regular ledges then 
reappeared. Another of my sons observed, on 
the inland side of Beachy Head, where the 
surface sloped at about 25^, many short little 
embankments like those just mentioned. 
They extended horizontally and were from a 
few inches to two or three feet in length. 
They supported tufts of grass growing vigor- 
ously. The average thickness of the mould 
of which they were formed, taken from nine 

s 



258 DENUDATION OF THE LAND. CHAP. VI. 

measurements, was 4*5 inches; while that of 
the mould above and beneath them was on an 
average only 3*2 inches, and on each side, on 
the same level, 3*i inches. On the upper parts 
of the slope, these embankments showed no 
signs of having been trampled on by sheep, 
but in the lower parts such signs were fairly 
plain. No long continuous ledges had here 
been formed. 

If the little embankments above the Cor- 
niche road, which Dr. King saw in the act of 
formation by the accumulation of disintegrated 
and rolled worm<astings, were to become 
confluent along horizontal lines, ledges would 
be formed. Each embankment would tend 
to extend laterally by the lateral extension of 
the arrested castings ; and animals grazing on 
a steep slope would ahnost certainly make use 
of every prominence at nearly the same level, 
and would indent the turf between them ; and 
such intermediate indentations would again 
arrest the castings. An irregular ledge when 
once formed would also tend to become more 
regular and horizontal by some of the castings 
rolling laterally from the higher to the lower 
parts, which would thus be raised. Any pro- 
jection beneath a ledge would not afterwards 



CHAP.YI. LEDGES ON HILL-SIDES. 259 

receive disintegrated matter from above, and 
would tend to be obliterated by rain and other 
atmospheric agencies. There is some analogy 
between the formation, as here supposed, of 
these ledges, and that of the ripples of wind- 
drifted sand as described by Lyell.* 

The steep, grass-covered sides of a 
mountainous valley in Westmoreland, called 
Grisedale, was marked in many places with 
innumerable lines of miniature cliffs, with 
almost horizontal, little ledges at their bases. 
Their formation was in no way connected 
with the action of worms, for castings could 
not anywhere be seen (and their absence is 
an inexplicable fact), although the turf lay in 
many places over a considerable thickness of 
boulder-clay and moraine rubbish. Nor, as 
far as I could judge, was the formation of 
these little cliffs at all closely connected with 
the trampling of cows or sheep. It appeared 
as if the whole superficial, somewhat argil- 
laceous earth, while partially held together by 
the roots of the grasses, had slided a little way 
down the mountain sides ; and in thus sliding, 
had yielded and cracked in horizontal lines, 
transversely to the slope. 

* * Elements of Geology,' 1865, p. aa 



260 DENUDATION OF THE LAND. CHAP. vi. 

Castings bbwn to leeward by the wind. — We 
have seen that moist castings flow, and that 
disintegrated castings roll down any inclined 
surface; and we shall now see that castings, 
recently ejected on level grass-covered surfaces, 
are blown during gales of wind accompanied 
by rain to leeward. This has been observed 
by me many times on many fields during 
several successive years. After such gales, 
the castings present a gently inclined and 
smooth, or sometimes furrowed, surface to 
windward, while they are steeply inclined or 
precipitous to leeward, so that they resemble 
on a miniature scale glacier-ground hillocks 
of rock. They are often cavernous on the 
leeward side, from the upper part having 
curled over the lower part During one un- 
usually heavy south-west gale with torrents 
of rain, many castings were wholly blown to 
leeward, so that the mouths of the burrows 
were left naked and exposed on the windward 
side. Recent castings naturally flow down 
an inclined surface, but on a grassy field, 
which sloped between lo*" and 15°, several 
were found after a heiavy gale blown up the 
slope. This likewise occurred on another 
occasion on a part of my lawn where the slope 



CHAP. VI. CASTINGS BLOWN TO LEEWARD. 26 1 

was somewhat less. On a third occasion, the 
castings on the steep, grass-covered sides of 
a valley, down which a gale had blown, were 
directed obliquely instead of straight down 
the slope; and this was obviously due to 
the combined action of the wind and gravity. 
Four castings on my lawn, where the down- 
ward inclination was o* 45', i^ 3"* and 3"* 30' 
(mean 2** 45') towards the north-east, after a 
heavy south-west gale with rain, were divided 
across the mouths of the burrows and weighed 
in the manner formerly described. The mean 
weight of the earth below the mouths of 
burrows and to leeward, was to that above 
the mouths and on the windward side as 
2i to I ; whereas we have seen that with 
several castings which had flowed down slopes 
having a mean inclination of 9"^ 26', and with 
three castings where the inclination was above 
1 2^ the proportional weight of the earth below 
to that above the burrows was as only 2 to i. 
These several cases show how efficiently gales 
of wind accompanied by rain act in displacing 
recently ejected castings. We may therefore 
conclude that even a moderately strong wind 
will produce some slight efiect on them. 

Dry and indurated castings, after their 



262 DENUDATION OF THE LAND. CHAP. VI. 

disintegration into small fragments or pellets^ 
are sometimes, probably often, blown by a 
strong wind to leeward. This was observed 
on four occasions, but I did not sufficiently 
attend to this point. One old casting on a 
gently sloping bank was blown quite away by 
a strong south-west wind. Dr. King believes 
that the wind removes the greater part of the 
old crumbling castings near Nice. Several 
old castings on my lawn were marked with 
pins and protected from any disturbance. 
They were examined after an interval of lo 
weeks, during which time the weather had 
been alternately dry and rainy. Some, which 
were of a yellowish colour had been washed 
almost completely away, as could be seen by 
the colour of the surrounding ground. Others 
had completely disappeared, and these no 
doubt had been blown away. Lastly, others 
still remained and would long remain, as 
blades of grass had grown through them. On 
poor pasture-land, which has never been rolled 
and has not been much trampled on by 
animals, the whole surface is sometimes dotted 
with little pimples, through and on which 
grass grows; and these pimples consist of 
old worm-castings. 



CHAP. VI. CASTINGS BLOWN TO LEEWARD. 263 

In all the many observed cases of soft cast- 
ings blown to leeward, this had been effected 
by strong winds accompanied by rain. As 
such winds in England generally blow from 
the south and south-west, earth must on the 
whole tend to travel over our fields in a north 
and north-east direction. This fact is interest- 
ing, because it might be thought that none 
could be removed from a level, grass-covered 
surface by any means. In thick and level 
woods, protected from the wind, castings will 
never be removed as long as the wood lasts ; 
and mould will here tend to accumulate to the 
depth at which worms can work. I tried to 
procure evidence as to how much mould is 
blown, whilst in the state of castings, by our 
wet southern gales to the north-east, over open 
and flat land, by looking to the level of the 
surface on opposite sides of old trees and 
hedge-rows; but I failed owing to the un- 
equal growth of the roots of trees and to most 
pasture-land having been formerly ploughed. 

On an open plain near Stonehenge, there 
exist shallow circular trenches, with a low 
embankment outside, surrounding level spaces 
50 yards in diameter. These rings appear very 
ancient, and are believed to be contemporaneous 



264 DENUDATION OF THE LAND. CHAP. VI. 

with the Druidical stones. Castings ejected 
within these circular spaces, if blown to 
the north-east by south-west winds would 
form a layer of mould within the trench, 
thicker on the north-eastern than on any other 
side. But the site was not favourable for the 
action of worms, for the mould over the 
surrounding Chalk formation with flints, was 
only 3*37 inches in thickness, from a mean of 
six observations made at a distance of 10 yards 
outside the embankment. The thickness of 
the mould within two of the circular trenches 
was measured every 5 yards all round, on the 
inner sides near the bottom. My son Horace 
protracted these measurements on paper ; and 
though the curved line representing the thick- 
ness of the mould was extremely irregular, yet 
in both diagrams it could be seen to be thicker 
on the north-eastern side than elsewhere. 
When a mean of all the measurements in both 
the trenches was laid down and the line 
smoothed, it was obvious that the mould was 
thickest in the quarter of the circle between 
north-west and north-east; and thinnest in 
the quarter between south-east and south- 
west, especially at this latter point. Besides 
the foregoing measurements, six others were 



CHAP. VI, CASTINGS BLOWN TO LEEWARD. 265 

taken near together in one of the circular 
trenches, on the north - east side ; and the 
mould here had a mean thickness of 2*29 
inches ; while the mean of six other measure- 
ments on the south-west side was only 1*46 
inches. These observations indicate that the 
castings had been blown by the south-west 
winds from the circular enclosed space into 
the trench on the north-east side; but many 
more measurements in other analogous cases 
would be requisite for a trustworthy result 

The amount of fine earth brought to the 
surface under the form of castings, and after- 
wards transported by the winds accompanied 
by rain, or that which flows and rolls down an 
inclined surface, no doubt is small in the course 
of a few scores of years ; for otherwise all the 
inequalities in our pasture fields would be 
smoothed within a much shorter period than 
appears to be the case. But the amount which 
is thus transported in the course of thousands 
of years cannot fail to be considerable and 
deserves attention. E. de Beaumont looks at 
the vegetable mould which everywhere covers 
the land as a fixed line, from which the 
amount of denudation may be measured.* 
* * Legons de Geologic pratique, 1845 * cinqui^me Le9on. 



266 DENUDATION OF THE LAND. CHAP. VI. 

He ignores the continued formation of fresh 
mould by the disintegration of the underlying 
rocks and fragments of rock ; and it is curious 
to find how much more philosophical were the 
views maintained long ago, by Playfair, who, 
in 1802, wrote, ** In the permanence of a coat of 
'' vegetable mould on the surface of the earth, 
'' we have a demonstrative proof of the con* 
** tinned destruction of the rocks." ♦ 

Ancient encampmenis and iumulu — E. de 
Beaumont adduces the present state of mamy 
ancient encampments and tumuli and of old 
ploughed fields, as evidence that the surface 
of the land undergoes hardly any degradation. 
But it does not appear that he ever examined 
the thickness of the mould over different parts 
of such old remains. He relies chiefly on 
indirect, but apparently trustworthy, evidence 
that the slopes of the old embankments are 
the same as they originally were; and it is 
obvious that he could know nothing about 
their original heights. In Knole Park a 
mound had been thrown up behind the rifle- 

All Elie de Beaumont* s arguments are admirably controverted 
by Prod A. Geikie in his essay in Transact Geolog. Soc. of 
Glasgow, voL iii. p. 153, 1868. 

* ' Illustrations of the Huttonian Theory of the Earth/ 
p. 107. 



CHAP. VI. ANCIENT MOUNDS. 267 

targets, which appeared to have been formed 
of earth originally supported by square blocks 
of turf. The sides sloped, as nearly as I could 
estimate them, at an angle of 45'' or 50"" with 
the horizon, and they were covered, especially 
on the northern side, with long coarse grass, 
beneath which many worm-castings were 
found. These had flowed bodily downwards, 
and others had rolled down as pellets. Hence 
it is certain that as long as a mound of this 
kind is tenanted by worms, its height will be 
continually lowered. The fine earth which 
flows or rolls down the sides of such a mound 
accumulates at its base in the form of a talus. 
A bed, even a very thin bed, of fine earth is 
eminently favourable for worms; so that a 
greater number of castings would tend to be 
ejected on a talus thus formed than elsewhere ; 
and these would be partially washed avray by 
every heavy shower and be spread over the 
adjoining level ground. The final result would 
be the lowering of the whole mound, whilst 
the inclination of the sides would not be greatly 
lessened. The same result would assuredly 
follow with ancient embankments and tumuli ; 
except where they had been formed of gravel 
or of nearly pure sand, as such matter is 



268 DENUDATION OF THE LAND. CHAP. VI. 

unfavourable for worms. Many old fortifica- 
tions and tumuli are believed to be at least 
2000 years old; and we should bear in mind 
that in many places about one inch of mould is 
brought to the surface in 5 years or two inches 
in ID years. Therefore in so long a period 
as 2000 years, a large amount of earth will 
have been repeatedly brought to the surface 
on most old embankments and tumuli, espe- 
cially on the talus round their bases, and much 
of this earth will have been washed completely 
away. We may therefore conclude that all 
ancient mounds, when not formed of materials 
unfavourable to worms, will have been some- 
what lowered in the course of centuries, although 
their inclinations may not have been greatly 
changed. 

Fields formerly ploughed. — From a very 
remote period and in many countries, land has 
been ploughed, so that convex beds, called 
crowns or ridges, usually about 8 feet across 
and separated by furrows, have been thrown 
up. The furrows are directed so as to carry 
off the surface water. In my attempts to 
ascertain how long a time these crowns and 
furrows last, when ploughed land has been 
converted into pasture, obstacles of many kinds 



CHAP. VI. ANCIENTLY PLOUGHED FIELDS, 269 

were encountered. It is rarely known when 
a field was last ploughed; and some fields 
which were thought to have been in pasture 
from time immemorial were afterwards dis- 
covered to have been ploughed only 50 or 60 
years before. During the early part of the 
present century, when the price of corn was 
very high, land of all kinds seems to have been 
ploughed in Britain. There is, however, no 
reason to doubt that in many cases the old 
crowns and furrows have been preserved from 
a very ancient period.* That they should 
have been preserved for very unequal lengths 
of time would naturally follow from the crowns, 
when first thrown up, having differed much in 
height in different districts, as is now the case 
with recently ploughed land. 

In old pasture fields, the mould, wherever 

* Mr. E. Tylor in his Presidential address ('Journal of the 
Anthropological Institute,' May 1880, p. 451) remaxks: 'Mt 
appears from several papers of the Berlin Society as to the 
German 'high-fields' or 'heathen-fields' (Hochkcker, and 
Heidenftcker) that they correspond much in their situation on 
hills and wastes with the 'elf-furrows' of Scotland, which 
popular mythology accounts for by the story of the fields 
having been put under a Papal interdict, so that people took to 
cultivating the hills. There seems reason to suppose that, like 
the tilled plots in the Swedish forest which tradition ascribes 
to the old ' hackers,' the German heathen-fields represent tillage 
by an ancient and barbaric population." 



270 DENUDATION OF THE LAND. CHAP. VI. 

measurements were made, was found to be 
from i to 2 inches thicker in the furrows than 
on the crowns ; but this would naturally follow 
from the finer earth having been washed from 
the crowns into the furrows before the land 
was well clothed with turf; and it is impossible 
to tell what part worms may have played in 
the work. Nevertheless from what we have 
seen, castings would certainly tend to flow and 
to be washed during heavy rain from the crowns 
into the furrows. But as soon as a bed of fine 
earth had by any means been accumulated in 
the furrows, it would be more favourable for 
worms than the other parts, and a greater 
number of castings would be thrown up here 
than elsewhere ; and as the furrows on sloping 
land are usually directed so as to carry off the 
surface water, some of the finest earth would 
be washed from the castings which had been 
here ejected and be carried completely away. 
The result would be that the furrows would 
be filled up very slowly, while the crowns 
would be lowered perhaps still more slowly by 
the flowing and rolling of the castings down 
their gentle inclinations into the furrows. 

Nevertheless it might be expected that old 
furrows, especially those on a sloping surface, 



CHAP. VI. ANCIENTLY PLOUGHED FIELDS. 27 1 

would in the course of time be filled up and 
disappear. Some careful observers, however, 
who examined fields for me in Gloucestershire 
and Staffordshire could not detect any dif- 
ference in the state of the furrows in the 
upper and lower parts of sloping fields, sup- 
posed to have been long in pasture ; and they 
came to the conclusion that the crowns and 
furrows would last for an almost endless 
number of centuries. On the other hand the 
process of obliteration seems to have com- 
menced in some places. Thus in a grass 
field in North Wales, known to have been 
ploughed about 65 years ago, which sloped at 
an angle of 15^ to the north-east, the depth 
of the furrows (only 7 feet apart) was care- 
fully measured, and was found to be about 
4^ inches in the upper part of the slope, and 
only I inch near the base, where they could 
be traced with difficulty. On another field 
sloping at about the same angle to the south- 
west, the furrows were scarcely perceptible 
in the lower part; although these same 
furrows when followed on to some adjoining 
level ground were from 2^ to 3^ inches in 
depth. A third and closely similar case was 
observed In a fourth case, the mould in a 



272 DENUDATION OF THE LAND. CHAP. Vf. 

furrow in the upper part of a sloping field 
was 2^ inches, and in the lower part 4^ inches 
in thickness. 

On the Chalk Downs at about a mile 
distance from Stonehenge, my son William 
examined a grass-covered, furrowed surface, 
sloping at from 8° to 10®, which an old shep- 
herd said had not been ploughed within the 
memory of man. The depth of one furrow 
was measured at 16 points in a length of 68 
paces, and was found to be deeper where the 
slope was greatest and where less earth would 
naturally tend to accumulate, and at the base 
it almost disappeared. The thickness of the 
mould in this furrow in the upper part was 
2^ inches, which increased to 5 inches, a little 
above the steepest part of the slope; and 
at the base, in the middle of the narrow 
valley, at a point which the furrow if con- 
tinued would have struck, it amounted to 7 
inches. On the opposite side of the valley, 
there were very faint, almost obliterated, 
traces of furrows. Another analogous but not 
so decided a case was observed at a few 
miles' distance from Stonehenge. On the 
whole it appears that the crowns and furrows 
on land formerly ploughed, but now covered 



CHAP. VI. MOULD OVER THE CHALK, 273 

with grass, tend slowly to disappear when the 
surface is inclined; and this is probably in 
large part due to the action of worms; but 
that the crowns and furrows last for a very 
long time when the surface is nearly level* 

Formatian and amount of mould over the 
Chalk Formation. — Worm-castings are often 
ejected in extraordinary numbers on steep, 
grass-covered slopes, where the Chalk comes 
close to the surface, as my son William ob- 
served near Winchester and elsewhere. If 
such castings are largely washed away during 
heavy rains, it is difficult to understand at 
first how any mould can still remain on our 
Downs, as there does not appear any evident 
means for supplying the loss. There is, more- 
over, another cause of loss, namely, in the 
percolation of the finer particles of earth into 
the fissures in the chalk and into the chalk 
itself. These considerations led me to doubt 
for a time whether I had not exaggerated the 
amount of fine earth which flows or rolls down 
grass-covered slopes under the form of cast- 
ings ; and I sought for additional information. 
In some places, the castings on Chalk Downs 
consist largely of calcareous matter, and here 
the supply is of course unlimited. But in 

T 



274 DENUDATION OF THE LAND. CHAP. VI. 

Other places, for instance on a part of Teg 
Down near Winchester, the castings were all 
black and did not effervesce with acids. The 
mould over the chalk was here only from 3 
to 4 inches in thickness. So again on the 
plain near Stonehenge, the mould, apparently 
free from calcareous matter, averaged rather 
less than 3^ inches in thickness. Why worms 
should penetrate and bring up chalk in some 
places and not in others I do not know. 

In many districts where the land is nearly 
level, a bed several feet in thickness of red 
clay full of unworn flints overlies the Upper 
Chalk. This overlying matter, the surface of 
which has been converted into mould, consists 
of the undissolved residue from the chalk. It 
may be well here to recall the case of the 
fragments of chalk buried beneath worm- 
castings on one of my fields, the angles of 
which were so completely rounded in the 
course of 29 years that the fragments now 
resembled water-worn pebbles. This must 
have been effected by the carbonic acid in the 
rain and in the ground, by the humus-acids, 
and by the corroding power of living roots. 
Why a thick mass of residue has not been left 
on the Chalk, wherever the land is nearly 



CHAP. VI. MOULD OVER THE CHALK. 275 

level, may perhaps be accounted for by the 
percolation of the fine particles into the fissures, 
which are often present in the chalk and are 
either open or are filled up with impure chalk, 
or into the solid chalk itself. That such 
percolation occurs can hardly be doubted. My 
son collected some powdered and fragmentary 
chalk beneath the turf near Winchester; the 
former was found by Colonel Parsons, RE., 
to contain lo per cent., and the fragments 
8 per cent, of earthy matter. On the flanks 
of the escarpment near Abinger in Surrey, 
some chalk close beneath a layer of flints, 
2 inches in thickness and covered by 8 inches 
of mould, yielded a residue of 37 per cent of 
earthy matter. On the other hand the Upper 
Chalk properly contains, as I was informed by 
the late David Forbes who had made many 
analyses, only from i to 2 per cent of earthy 
matter; and two samples from pits near my 
house contained i'3 and o'6 per cent I 
mention these latter cases because, from the 
thickness of the overlying bed of red clay with 
flints, I had imagined that the underlying 
chalk might here be less pure than elsewhere. 
The cause of the residue accumulating more in 
some places than in others, may be attributed 



276 DENUDATION OF THE LAND. CHAP. VI. 

to a layer of argillaceous matter having been 
left at an early period on the chalk, and this 
would check the subsequent percolation of 
earthy matter into it 

From the facts now given we may conclude 
that castings ejected on our Chalk Downs 
suffer some loss by the percolation of their 
finer matter into the chalk. But such impure 
superficial chalk, when dissolved, would leave 
a lai^r supply of earthy matter to be added 
to the mould than in the case of pure chalk. 
Besides the loss caused by percolation, some 
fine earth is certainly washed down the sloping 
grass-covered surfaces of our * Downs. The 
washing-down process, however, will be 
checked in the course of time; for although 
I do not know how thin a layer of mould 
suffices to support worms, yet a limit must 
at last be reached; and then their castings 
would cease to be ejected or would become 
scanty. 

The following cases show that a consider- 
able quantity of fine earth is washed down. 
The thickness of the mould was measured at 
points 12 yards apart across a small valley 
in the Chalk near Winchester. The sides 
sloped gently at first; then became inclined 



CHAP. VI. MOULD OVER THE CHALK. 277 

at about 20^; then more gently to near the 
bottom, which transversely was almost level 
and about 50 yards across. In the bottom, 
the mean thickness of the mould from five 
measurements was 8-3 inches; whilst on the 
sides of the valley, where the inclination varied 
between 14^ and 20^, its mean thickness was 
rather less than 3*5 inches. As the turf- 
covered bottom of the valley sloped at an 
angle of only between 2^ and 3°, it is probable 
that most of the 8'3-inch layer of mould had 
been washed down from the flanks of the 
valley, and not from the upper part But as 
a shepherd said that he had seen water flowing 
in this valley after the sudden thawing of 
snow, it is possible that some earth may have 
been brought down from the upper part; or, 
on the other hand, that some may have been 
carried further down the valley. Closely 
similar results, with respect to the thickness 
of the mould, were obtained in a neighbouring 
valley. 

St. Catherine's Hill, near Winchester, is 
327 feet in height, and consists of a steep cone 
of chalk about i of a mile in diameter. The 
upper part was converted by the Romans, or, 
as some think, by the ancient Britons, into an 



278 DENUDA';*ION OF THE LAND. CHAP. VL 

encampment, by the excavation of a deep and 
broad ditch all round it Most of the chalk 
removed during the work was thrown upwards, 
by which a projecting bank was formed ; and 
this effectually prevents worm-castings (which 
are numerous in parts), stones, and other 
objects from being washed or rolled into the 
ditch. The mould on the upper and fortified 
part of the hill was found to be in most places 
only from 2^ to 3^ inches in thickness; 
whereas it had accumulated at the foot of the 
embankment above the ditch to a thickness 
in most places of from 8 to 9^ inches. On 
the embankment itself the mould was only 
I to i^ inch in thickness ; and within the ditch 
at the bottom it varied from 2^ to 3^, but was 
in one spot 6 inches in thickness. On the 
north-west side of the hill, either no embank- 
ment had ever been thrown up above the 
ditch, or it had subsequently been removed ; 
so that here there was nothing to prevent 
worm-castings, earth and stones being washed 
into the ditch, at the bottom of which the 
mould formed a layer from 11 to 22 inches in 
thickness. It should however be stated that 
here and on other parts of the slope, the bed 
of mould often contained fragments of chalk 



CHAP. VI. MOULD OVER THE CHALK. 279 

and flint which had obviously rolled down at 
different times from above. The interstices 
in the underlying fragmentary chalk were also 
filled up with mould. 

My son examined the surface of this hill to 
its base in a south-west direction. Beneath 
the great ditch, where the slope was about 
24*^, the mould was very thin, namely, from 
i^ to 2^ inches; whilst near the base, where 
the slope was only 3^ to 4^, it increased to 
between 8 and 9 inches in thickness. We 
may therefore conclude that on this artificially 
modified hill, as well as in the natural valleys 
of the neighbouring Chalk Downs, some fine 
earth, probably derived in large part from 
worm-castings, is washed down, and accumu- 
lates in the lower parts, notwithstanding the 
percolation of an unknown quantity into the 
underlying chalk; a supply of fresh earthy 
matter being afforded by the dissolution of 
the chalk through atmospheric and other 
agencies. 



28o CONCLUSION. CHAP. VII. 



CHAPTER VII. 

CONCLUSION. 

Summary of the part which worms have played in the history 
of the world— Their aid in the disintegration of rocks^In 
the denudation of the land-^In the preservation of ancient 
remains — In the preparation of the soil for the growth of 
plants — Mental powers of worms— -Conclusion. 

Worms have played a more important part 
in the history of the world than most persons 
would at first suppose. In almost all humid 
countries they are extraordinarily numerous, 
and for their size possess great muscular 
power. In many parts of England a weight 
of more than ten tons (10,516 kilogrammes) 
of dry earth annually passes through their 
bodies and is brought to the surface on each 
acre of land; so that the whole superficial 
bed of vegetable mould passes through their 
bodies in the course of every few years. 
From the collapsing of the old burrows the 
mould is in constant though slow movement, 
and the particles composing it are thus rubbed 



CHAP. VII. CONCLUSION. 281 

together. By these means fresh surfaces are 
continually exposed to the action of the car- 
bonic acid in the soil, and of the humus-acids 
which appear to be still more efficient in the 
decomposition of rocks. The generation of 
the humus-acids is probably hastened during 
the digestion of the many half-decayed leaves 
which worms consume. Thus the particles of 
earth, forming the superficial mould, are sub- 
jected to conditions eminently favourable for 
their decomposition and disintegration. More- 
over, the particles of the softer rocks suffer 
some amount of mechanical trituration in the 
muscular gizzards of worms, in which small 
stones serve as mill-stones. 

The finely levigated castings, when brought 
to the surface in a moist condition, flow during 
rainy weather down any moderate slope ; and 
the smaller particles are washed far down even 
a gently inclined surface. Castings when dry 
often crumble into small pellets and these are 
apt to roll down any sloping surface. Where 
the land is quite level and is covered with 
herbage, and where the climate is humid so 
that much dust cannot be blown away, it 
appears at first sight impossible that there 
should be any appreciable amount of sub-aerial 



282 CONCLUSION. CHAP. VII. 

denudation ; but worm-castings are bIown» 
especially whilst moist and viscid, in one uni- 
form direction by the prevalent winds which 
are accompanied by rain. By these several 
means the superficial mould is prevented 
from accumulating to a great thickness; and 
a thick bed of mould checks in many ways 
the disintegration of the underlying rocks and 
fragments of rock. 

The removal of worm-castings by the above 
means leads to results which are far from in- 
significant It has been shown that a layer 
of earth, *2 of an inch in thickness, is in many 
places annually brought to the surface ; and if 
a small part of this amount flows, or rolls, or is 
washed, even for a short distance, down every 
inclined surface, or is repeatedly blown in one 
direction, a great effect will be produced in the 
course of ages. It was found by measurements 
and calculations that on a surface with a mean 
inclination of 9^ 26', 2*4 cubic inches of earth 
which had been ejected by worms crossed, in 
the course of a year, a horizontal line one yard 
in length ; so that 240 cubic inches would cross 
a line 100 yards in length. This latter amount 
in a damp state would weigh 11^ pounds. 
Thus a considerable weight of earth is 



CH^. VII. CONCLUSION. 283 

continually moving down each side of every 
valley, and will in time reach its bed. Finally 
this earth will be transported by the streams 
flowing in the valleys into the ocean, the great 
receptacle for all matter denuded from the 
land. It is known from the amount of sedi- 
ment annually delivered into the sea by the 
Mississippi, that its enormous drainage-area 
must on an average be lowered '00263 of an 
incli each year ; and this would suffice in four 
and half million years to lower the whole 
drainage-area to the level of the sea-shore. 
So that, if a small fraction of the layer of 
fine earth, *2 of an inch in thickness, which 
is annually brought to the surface by worms, 
is carried away, a great result cannot fail to be 
produced within a period which no geologist 
considers extremely long. 

Archaeologists ought to be grateful to 
worms, as they protect and preserve for an 
indefinitely long period every object, not liable 
to decay, which is dropped on the surface of 
the land, by burying it beneath their castings. 
Thus, also, many elegant and curious tesselated 
pavements and other ancient remains have 
been preserved ; though no doubt the worms 



284 CONCLUSION. CHAP. VII. 

have in these cases been largely aided by 
earth washed and blown from the adjoining 
land, especially when cultivated. The old tesse- 
lated pavements have, however, often suffered 
by having subsided unequally from being un- 
equally undermined by the worms. Even old 
massive walls may be undermined and subside ; 
and no building is in this respect safe, unless 
the foundations lie 6 or 7 feet beneath the 
surface, at a depth at which worms cannot 
work. It b probable that many monoliths 
and some old walls have fallen down from 
having been undermined by worms. 

Worms prepare the ground ♦ in an excel- 
lent manner for the growth of fibrous-rooted 
plants and for seedlings of all kinds. They 
periodically expose the mould to the air, and 
sift it so that no stones larger than the particles 
which they can swallow are left in it. They 
mingle the whole intimately together, like a 
gardener who prepares fine soil for his choicest 
plants. In this state it is well fitted to retain 
moisture and to absorb all soluble substances, 
as well as for the process of nitrification. The 

* White of Selborne has some good remarks on the service 
performed by worms in loosening, &c., the soil Edit by 
L. Jenyns, 1843, P- 281. 



CHAP. VII. CONCLUSION. 285 

bones of dead animals, the harder parts of 
insects, the shells of land-molluscs, leaves, 
twigs, &c, are before long all buried beneath 
the accumulated castings of worms, and are 
thus brought in a more or less decayed state 
within reach of the roots of plants. Worms 
likewise drag an infinite number of dead leaves 
and other parts of plants into their burrows, 
partly for the sake of plugging them up and 
partly as food. 

The leaves which are dragged into the 
burrows as food, after being torn into the finest 
shreds, partially digested, and saturated with 
the intestinal and urinary secretions, are com- 
mingled with much earth. This earth forms 
the dark coloured, rich humus which almost 
everywhere covers the surface of the land 
with a fairly well-defined layer or mantle. 
Hensen* placed two worms in a vessel 
18 inches in diameter, which was filled with 
sand, on which fallen leaves were strewed; 
and these were soon dragged into their 
burrows to a depth of 3 inches. After about 
6 weeks an almost uniform layer of sand, a 
centimeter ('4 inch) in thickness, was converted 

* ^Zeitschrift fiir wissenschaft. Zoolog.' B. xxviii. 1877, 
p. 360. 



286 CONCLUSION. CHAP. vii. 

into humus by having passed through the 
alimentary canals of these two worms. It 
is believed by some persons that worm- 
burrows, which often penetrate the ground 
almost perpendicularly to a depth of 5 or 6 
feet, materially aid in its drainage ; notwith- 
standing that the viscid castings piled over 
the mouths of the burrows prevent or check 
the rain-water directly entering them. They 
allow the air to penetrate deeply into the 
ground. They also greatly facilitate the down- 
ward passage of roots of moderate size ; and 
these will be nourished by the humus with 
which the burrows are lined. Many seeds 
owe their germination to having been covered 
by castings ; and others buried to a consider- 
able depth beneath accumulated castings lie 
dormant, until at some future time they are 
accidentally uncovered and germinate. 

Worms are poorly provided with sense- 
organs, for they cannot be said to see, although 
they can just distinguish between light and 
darkness ; they are completely deaf, and have 
only a feeble power of smell ; the sense of 
touch alone is well developed. They can 
therefore learn but little about the outside 
world, and it is surprising that they should 



CHAP. VII. CONCLUSION. 287 

exhibit some skill in lining their burrows with 
their castings and with leaves, and in the case 
of some species in piling up their castings into 
tower-like constructions. But it is far more 
surprising that they should apparently exhibit v 
some degrees of intelligence instead of a mere 
blind mstinctive impulse, in their mannw of 
plugging up the mouths of their burrows. 
They act in nearly the same manner as would 
a man, who had to close a cylindrical tube 
with different kinds of leaves, petioles, triangles 
of paper, &c., for they commonly seize such 
objects by their pointed ends. But with thin 
objects a certain number are drawn in by their 
broader ends. They do not act in the same 
unvarying manner in all cases, as do most of 
the lower animals ; for instance, they do not 
drag in leaves by their foot-stalks, unless the 
basal part of the blade is as narrow as the 
apex, or narrower than it 

When we behold a wide, turf-covered ex- 
panse, we should remember that its smoothness, 
on which so much of its beauty depends, is 
mainly due to all the inequalities having been 
slowly levelled by worms. It is a marvellous 
reflection that the whole of the superficial 



288 CONCLUSION. CHAP. Vll. 

mould over any such expanse has passed, and 
will again pass, every few years through the 
bodies of worms. The plough is one of the 
most ancient and most valuable of man's inven- 
tions ; but long before he existed the land was 
in fact regularly ploughed, and still continues 
to be thus ploughed by earth-worms. It may 
be doubted whether there are many other 
animals which have played so important a part 
in the history of the world, as have these lowly 
organi2ed creatures. Some other animals, 
however, still more lowly oi^ganized, namely 
corals, have done far more conspicuous work 
in having constructed innumerable reefs and 
islands in the great oceans ; but these are 
almost confined to the tropical zones. 



INDEX. 



Abinger, Roman villa at, 166 

i castings from Roman villa at, with roonded particles, 232 

Acids of humus, action on rocks, 219 

Africa, dust from, 213 

Air, currents of, worms sensitive to, 26 

Amount of earth brought to the surface by worms, 121 

Ants, intelligence of, 88 

Archiac, D\ criticbms on my views, 4 

Artemisia, leaves of, not eaten by worms, 31 

Ash-tree, petioles of, 75 

Beaulieu Abbey, burial of the old pavement, 179 

— , castings from, with rounded particles, 233 

Beaumont, Elie de,on vegetable mould, 2 

on the rubbish underlying great cities, 165 

on the transport of dust, 215 



- on the permanence of mould, 265 
on the permanence of ancient tumuli, 266 



Beech-forests, stones not buried under by castings, 13s 
Bengal, worms of; 116 
Boa-constrictor lubricating its prey, 41 
Bones, crushed, burial of, under castings, 136 
Brading, Roman villa at, 185 

, castings from, with rounded particles, 233 

Bridgman, Mr., on worms eating leaves of a Phlox, 31 
Buckman on grasses profiting by being rolled, 9 
Burial of the remains of ancient buildings by worms, 164 
Burrows, depth of, 103 

direction o^ on a slope, 247 

excavation of, 93 

U 



290 INDEX. 

Burrows lined with black earth, 104 
lined with leaves, 105 



mouths of, worms lie motionless near, 14 

oldy collapse, i x i 

plugged up, ss 

terminating in a small chamber, often lined with stones 

or seeds, 107 

Calciferous glands, i6| 41 
Cannibal worms, 34 
Carabus attaddng worms, 59 
Camagie, Mr., depth of burrows, 108 
Castings, acid, 49 

from Beaulieu, 96 

in cellars, 100 

tower-like, near Nice, 100 

ejection of, 109 

tower-like, from near Calcutta, 1 16 

of great size on the Nilgiri Mountains, 118 

weight o^ from a single burrow and from a given area, 

- thickness of layer formed from, during a year, 1 57 

- ejected over ancient buildings, 231 

- flowing down slopes, 239 

- washed away, 249 
■ dry, disintegration of, 252 



149 



blown to leeward, 260 

Cellars, castings in, 100 

Cells, free, with calcareous matter in the calciferous glands, 45 

Cellulose, digestion of, 3$ 

Chalk-formation, surface of, much denuded, 128 

Chalk, residue of, forming a superficial deposit, 129 

fragments of, soon buried and corroded, 130 

formation of mould over, 273 

Chedworth, Roman villa of, 183 

Circular trenches near Stonehenge, 263 

ClaparMe on the structure of the intestines of worms, 17 

on the salivary glands of worms, 40 

on the calciferous glands, 41 

on the pharynx adapted for suction, 53 

< doubts wheUier earth serves worms as food, 97, 100 



INDEX. 291 

ClaparMe on the gizzards of worms, 225 

ClematiSy petioles of, used in plugging up burrows, J J, 74 

Cobra^snake, intelligence o( 90 

Collapsing of old burrows, 1 1 1 

Concluding remarks, 280 

Concretions of lime in the anterior calciferous glands, 43 

calcareous, use.of, 51 

Corals, mud derived from, 234 

Comiche road, disintegrated castings on, 253, 258 

Croll, Mr., on denudation, 212 

Crowns or ridges on old ploughed fidds, 268 

Currents of air, worms sensitive to, 26 

Dancer, Mr., on the action and number of worms, 136, 149 

Deafness of worms, 24 

D^ris over the Roman remains at Silchester, 186 

Decay of leaves not hastened by the secretion with which they 

are bathed, 36 
Denudation of the land, 209 
Depth to which worms burrow, 103 
Digaster, 225 
Digestion of worms, 34 

extra-stomachal, 4 1 

Disintegration of rocks aided by worms, 214 

Distribution of worms, 113 

Down, amount of earth here brought annually to the surfitce, 

128 
Downs near Winchester, valleys in, 277 
Dust, distance transported, 214-216 

Earth, amount of, brought to the surface by worms, 121 

amount of, which flows down a given slope, 243 • 

swallowed as food, 95 

weight of, ejected from a single burrow, 149 

Eisen on the number of species of worms, 8 

on the depth of burrows, 103 

Ejection of castings, 109 
Embankments on hill-sides, 255, 258 
Encampments, ancient, 266 
Ernst, Dr., on worms at Caracas, 1 14 
Excavation of the burrows, 93 



292 INDEX. 

Fabre, M., on the instincU of Sphex, 89 

Fairer, Mr. T. H^ on the Roman villa at Abinger, 166-17S 

Fat eaten by worms, 35 

Fields fo.merly ploughed, 268 

Fish, Mr., criticisms on my views, 5 

Flints standing vertically in the residue over the chalk. 129 

acted on externally and internally by atmospheric 

agencies, 224 
Flowing down of castings, 239 
Fluid, digestive, of worms, 34 
Food of worms, leaves, 33 

earth, 95 

Foster, Michael, on the pancreatic ferment, 35 
on the acidity of the contents of the intestines, 

Foundations, deep, of the Roman buildings at Wroxeter, 206 
Fredericq, L^n, on the digestive juice of worms, 34 
Furrows on old ploughed fields, 269 

Galton, Mr., on the number of dead worms, 12 
Geikie, Archibald, on Denudation, 212 
—-*——— controverts £. de Beaumont's views on 
Denudation, 266 

f James, controverts Richthofen's views, 216 

- on glaciated rocks, 224 



Geographical distribution of worms, 113 

Gilbert, Dr., on the amount of nitrogen in worm-castings, 220 

Giszards of worms, 22s 

Glands, calciferous, 16, 41 

function of, 46 

Glen Roy, evidence of rarity of debacles, 238 

HaasI, Von, on aboriginal instruments in New Zealand found 

buried, 138 
Hearing, sense of, 24 
Heat, perception of, 23 
Heaths, inhabited by few worms, except where paths cross 

them, 9 
Hensen on the number of worms in gardens, 4 
on worms not subsisting on earth, 103 



- on the depth of burrows, 103 



INDEX, 293 

Hensen on number of worms living in a given area, 148 

on the composition of mould, 217 

on the amount of humus formed by two worms, 285 

Henslow, Prof^ on ledges on hill-sides, 255 
Hofiineister, number of species of worms, 8 

on worms hybemating in company, 32 

, perception of light by worms, 18, 20 

on the enemies of worms, 59 

depth of burrows, 103 

on hybernation of worms, 107 

Hooker, Sir J., on ledges of earth on the Himalaya, 255 
Homer, Mr., on castings in a cellar, 100 
Humus acids, action of, on rocks, 219, 223 

Instinct of worms, 32 

Intelligence of worms, 33, 61 

Intestines of worms, their contents acid, 48 

Islands inhabited by worms, 1 13 

Johnson, Dr. H., on the Roman remains at Wroxeter, 202-207 
on ammonia in worm-castings, 220 



, S. W., * How Crops Feed,' 220 

Joyce, Rev. J. G^ on the Roman remains at Silchester, 187 
Julien, Mr. A. A., on the composition of peat, 217 
on the humus-adds, 219, 223 

Key, Rev. H., on the burial of cinders by worms, 136 
King, Dr., on the formation of mould in forests in France, 5 

on castings near Nice, 100, no 

on great castings on the Nilgiri Mountains and in 

Ceylon, 118 

weight of castings near Nice^ 152 

on disintegrated castings on the Corniche road, 253, 

258 

- on the washing away of the castings on the Nilgiri 



Mountains, 251 
Knole Park beech-woods, worms absent from, 10 
Koninck, De, on the disintegration of rocks, 214 
Krukenberg on the digestive fluid of worms^ 34 

Laburnum leaves, 64 

U3 



294 INDEX. 

Land, denudation of, 270 

Lankester, Ray, on the structure of worms, 15 

on worms from Kerguelen Land, 114 

La Plata, dust storms of, 215 

Layard, Mr., on the habits of the cobra, 90 

Leaves, worms distinguish the taste of different kinds of, 30 

consumed by worms, 33 

their decay not hastened by the alkaline secretion with 

which they are bathed, 36 

decayed, generate acids, 47 

— — used in plugging up burrows, 61 
- used to line burrows, 105 



Ledges of earth on hill-sides, 256 
Light, perception of, by worms, 18 
Lime, carbonate of, concretions of, 42 

Maer Hall, amount of earth brought to surface, 122 

Mallett, Mr., on the sinking of the ground under great buildings, 

147 

Meat, raw, eaten by worms, 34 

Mental qualities of worms, 31 

Mint, leaves of, only nibbled, 31 

Mississippi, drainage area of, 212 

Moles pursuing worms, 25 

M6bius on the habits of a pike, 89 

Moniligaster, 225 

Moorhouse, Mr., on peewits beating the ground, 26 

Morren on worms surviving long immersion, 1 1 

on worms lying motionless near mouths of their bur- 
rows, 14 

- on worms eating sugar, 33 



on the disappearance of the calciferous glands during 

winter, 46 

- on stones in the gizzards of worms, 226^ 228 



Mould, thickness of, annually ejected by worms, 157 

thickness o^ over Roman remains at Chedworth, 184 

nature and thickness of, over the Roman remains at 

SQchester, 198 

thickness of, at Wroxeter, 202 

' formation and thickness of, over the chalk, 273 



Mountains, worms absent from, 11 



INDEX. 295 

MuUer, Fritz, on the worms in South Brazil, lis 
, P. E., on earthworms, 6 

Nice, castings near, 100 

disintegrated castings near, 253 

Night, worms leave their burrows at, 13 
Nilgiri Mountains, castings on, 118 

Objects strewed on the sur£au:e soon buried under castings, 122 
Obliteration of old furrows on ploughed land, 269 
Odours, degree of sensitiveness to, by worms, 27 

Pancreatic secretion, 35 

not acid, 50 

Paper, triangles of, 78 

Parfitt, Mr^ on the closing of the mouths of burrows, 60 

Path, paved, burial of, by worm-castings, 135 

Paths inhabited by worms, 9 

Pavement, modem, undermined by worms, 179 

Pavements, ancient, subsidence of, at Silchester, 194 

Peat, formation of, 217 

Peewits beating the ground, 26 

Percolation of earth into the chalk, 273 

Perichaeta, naturalized near Nice, loi 

Perrier, worms surviving long immersion, 1 1 

on the caldferous glands, 41 

on the action of the [larynx, 53 

on the burrowing power of worms, 93 

on naturalized worms, loi 



• on worms killed by acetic acid, 149 
- on the gizzards of worms, 225, 228 



Petioles of Qematis, 74 

of the ash, 75 

Pharynx, action of, 53 

Pike, stupidity of, 89 

Pine-leaves used in plugging up burrows, 55, 67 

— — lining burrows, 106 

Pipes, formation of, in the chalk, 12^ 

Playfair on Denudation, 266 

Ploughed fields, old, 269 

Plugging up of the burrows, 5^ 



^9^ INDEX. 

Plugging^ use of the process, 59 
Prehensioiii power of, by wormSi 53 

Qualities, mental, of worms, 31 

Ramsay, Mr., on the sinkiaig of a pavement undermined by 
worms, 179 

on Denudation, 210 

Remains, ancient, buried by worms, 164 

Rhododendron leaves, 65 

Richthofen on dust deposits in Chhia, 215 

Robinia, petioles of, 77 

Rocks, disint^ration of, aided by worms, 218 

triturated in the gizzards of worms, 228 

Rolling down of dry castings, 253 

Romanes, Mr., on tht intelligence of animals, 90 

Sachs on living roots corroding rocks, 222 

Sage, leaves of, not eaten by worms, 31 

Saliva, doubtful whether any secreted by worms, 40 

Saussure, H. de, on brick-pebbles, 232 

Schmulewitsch on the digestion of cellulose, 35 

Scolopendra attacking worms, 59 

Scott, Mr. J., on worms near Calcutta, 115 

Seeds preserved in the burrows of worms, 109 

Semper on various animals swallowing sand, 97 

Senses of worms, 17 

Silchester, old Roman town, 186 

Silica, colloid, acted on by the humus-acids, 220 

Simpson, Mr., on worms dragging leaves, 55 

Sinking of the pavements at Silchester, 194 

Sites inhabited by worms, 8 

Smell, sense o^ 27 

Social feelings of worms, 32 

Sorby, Mr., on the trituration of small particles of rock, 235 

Stanley on peewits beating the ground, 26 

Starch eaten by worms, 34 

digestion of the granules in the cells of leaves, 40 

St. Catherine's Hill, near Winchester, 277 
Stones, great, undermined by worms at Leith Hill and at 
Stonehenge, 139 



INDEX. 297 

Stones, small, heaped over burrows, 57 

small, in the gizzards of worms, 226 

rounded in the gizzards of worms, 228 

Stonehenge, great stones of, undermined by worms, 144 

_ circular trenches near, 263 

Structure of worms, 1 5 

Sturtevant, Dr., on worms found coiled together, 32 

Subsidence of the pavements at Silchester, 194 

Suction, power of, 53 

Sugar eaten by worms, 33 

Summary of whole book, 280 

Surface, objects strewed on, buried under castings, 122 

Taste, power of, 30 

Thickness of the layer of mould annually ejected by worms, 157 

of the mottkl over the remains at Chedworth, 184 

of the mould over the remains at Silchester, 198 

of the mould over the Roman remains at Wroxeter, 

202 
Thyme, leaves of, not eaten by worms, 31 
Touch, worms highly sensitive to, 26 
Triangles of paper, 78 

Trituration of particles of rock in the gizzards of worms, 227 
Tumuli, ancient, 267 
Tylor, Mr. A., on Denudation, 212 

■ , Mr. £., on anciently ploughed land, 269 
TyphlosoliSy 17 

Utricularia, bladders of, 103 

Vibrations, worms sensitive to, 24 
Vision, power of, in worms, 18 

Wallace, Mr. J., on worm-burrows, 244 

Walls, ancient, at Abinger, penetrated by worms, 175 

penetrated by worms at Silchester, 192 

Washing away of castings, 250 

Wedgwood, Mr., on the formation of mould, 3 

Weight of earth ejected from a single burrow, 149 

Whitaker, Mr., on Denudation, 211 

White on worms leaving their burrows at night, 1 3 



298 INDEX. 

Winchester^ chalk formation near, 277 
Wind, action o^ on castings, 260 
Worms, noctarnal, 12 

large numbers occasionally die, 1 3 

dead eaten by other worms, 34 

contents of intestines acid, 48 

their castings acid, 49 

power of suction, 53 

plugging up their burrows, 55 

intelligence of, 61 

formation of their burrows, 93 

number of, living in a given area, 148 

penetrating ancient walls, 175, 192 

gizzards of, and the trituration of the contained stones, 

225 

prefer to live in fine earth, 267 

Wright, Mr., on the age of Wroxeter, 200 
Wroxeter, old Roman town of, 200 

Zincke, Rev. F. B., on celts found at a depth of three feet, 136 



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DARWI N'S WORKS AH D LIFL 

THE CORRECTED COPYRIGHT EDITION. 

THE ORIGIN OF SPECIES BY MEANS OF NATURAL 
SELECTION. Libraiy Edition, a vols, xsf.— Popular Edition. Crown 
8vo, &.— Cheaper Editioo. With Portrait, ^s, 6/. net— Also in Paper 
Cover, ij. net 

JOURNAL OF A NATURALIST DURING A VOYAGE 
ROUND THE WORLD IN WM,^, BRAGLB. With xoo lUustraUons. 
Medfaim 8vo. ax;.— Popular Edition, $;. 61/.— Cheaper Edition. With 
a Portrait and 16 Ilhistrations. Lai^ge crown 8vo, af . 6(/. net 

DESCENT OF MAN, AND SELECTION IN RELATION 
TO SEX. Woodcuts. Library Edition, a vols. I5c«— Popular Edition. 
7J. 6t/.— Cheaper Edition, af. td^ net. 

FORMATION OF VEGETABLE MOULD THROUGH 
THE ACTION OF WORMS. Illustrations. 6r.*-Cbeap EdiUon. 
2x. f>d, net 

VARIATION OF ANIMALS AND PLANTS UNDER 
DOMESTICATION. Woodcuts, a vols. ly. 

EXPRESSION OF THE EMOTIONS IN MAN AND 

ANIMALS. With Illustrations, xaf. 

VARIOUS CONTRIVANCES BY WHICH ORCHIDS ARE 
FERTILIZED BY INSECTS. Woodcuts. 7J. 6rf. 

MOVEMENTS AND HABITS OF CLIMBING PLANTS. 
Woodcuts. 6j. 

INSECTIVOROUS PLANTS. Woodcuts, gx. 

CROSS AND SELF-FERTILIZATION IN THE VEGE- 
TABLE KINGDOM. 9;. 

DIFFERENT FORMS OF FLOWERS ON PLANTS OF 
THE SAME SPECIES. 71. td. 

MORE LETTERS OF CHARLES DARWIN. A Record 

of his Work in a Series of hitherto Unpublished Letters. Edited by 

Francis Darwin, Fellow of Christ's CoU^, and A. C. Sbward, Fellow 

of Emmanuel College, Cambridge. With Portraits, a vols. Demy 8vo. 

3af . net. 

" Abundant letten. written through the yeeis and talltB^ of his thoo^its* bti plans 

of work, his hopes ana his doubts, written some to the dearest and meet intiauue friends 

and others to comparative strangen valued for their sympathy and help in work, are 

nothing more nor lesft than a revehtaoo of the man. . . . These lecten have a denntte 

and immeasurable value for the scientific naturalist. . . . The present collection b 

arranged in sul^ects and conuins a great deal of very great importance."— 7*Ar Timet* 

LIFE AND LETTERS OF CHARLES DARWIN. With 
an Autobiographical Chapter. Edited by Francis Darwin, F.R.S. 
With 3 PortraiU and Illustrations. 3 vols. 8vo, 3&r. 

CHARLES DARWIN : An Autobiography. With Selections 
from his Letters by F*RANCis Darwin. Portrait, yj. 6<f.— Cheaper 
Edition. With Portrait. Lai^ge crown avo, ai. 6^. net. 



JOHN MURRAY, ALBEMARLE STREET, W. 



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iTiMfx z'( 1964 




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